Not sure where to post this.

Sometimes, when I write, I have these great moments of inspiration where words and ideas just pours out, and I'm loving what I'm coming up with...

For me, moments like this are almost always followed by what I call the "creative hangover," which is to say, serious doubt and depression over what I had just come up with the night before, or even a few hours before, during those moments of "inspiration."

It's like manic depression! It's exhausting! And makes it difficult to finish anything.

Has anyone else experienced this? How do you deal with it?

It's called being in the zone and it's perfectly normal and something you want.  And it's good to have doubts because you might want to rewrite but get rid of the depression because it doesn't have any productive outcome.   Or else it could be possible you need some depression in order to be inspired like tulips need a freeze.  I know that often my most creative things happen while I'm getting over being depressed.

Yeah, I get a little up and down with writing.  With me, I constantly have ideas like little snippets or photographs that continually spin in a circle in my head.  The hard part is getting one or a couple of those snippets to stop spinning long enough to get an feasible idea out of them.

the spinning images I describe like the carousel candle - where you move the outside with cut-outs of horses, etc and the light of the candle acts as a motion - that's pretty much what my head does with ideas.  

I usually start out really good and blaze through the first few pages maybe 10-20, then, I start to second guess myself and get in a bit of a rut. What helps me is either putting the script aside for a little while, as short as a few days or as long as a month or two and come back to it.  Another more used option is I head to the theater to watch a film - as the theater is an escape for me, but I always carry a notebook to me into the auditorium.  I get inspired by films I see, and can usually conjure up an idea from it or at least something in a scene will get my juices flowing again.

Just don't think about the $12 you spend to get in - that can send someone into depression like a lightning rod

Quoted from mattman2900 I usually start out really good and blaze through the first few pages maybe 10-20, then, I start to second guess myself and get in a bit of a rut. What helps me is either putting the script aside for a little while, as short as a few days or as long as a month or two and come back to it.

You are describing classic linear thinking.
Like any bold explorer, you get a notion to "go" in a specific direction until... I guess you either "get there" or say "screwwit".

Another approach would be more along the lines of saturant thinking, like dropping a paper towel on a puppy piddle: multiple piddle points begin, then all saturate out to connect together into a whole.
By this method you rough out a beginning, middle and end plus however many supporting rough details you have - while your fire is burning!
Your infamous 10 to 20 pages.

Later, you send your thoughts to work on the bits and pieces in between until the story fills in.
Tweak it, bend it, rerun it until it's functional.

Kill the beast.
Chop off it's limbs and head. Gut it.
Take a break.
Go to work on breaking down it's individual parts until the whole is processed.

Starting at the nose and working your way to the tail explains why you "creatively fatigue" at somewhere around the shoulders, the 10-20 pg point.
Hardly edible.

Quoted from RayW You are describing classic linear thinking. Like any bold explorer, you get a notion to "go" in a specific direction until... I guess you either "get there" or say "screwwit".

oops, "usually" should not have made it's way in there, in that term.
I never necessarily say "screw it" If I do that, then the likely hood of me coming back to it is nullified.  I usually can return to script within a couple of days - I let the story work itself out it my head (the images stop, and I'm focused). I do have multiple ideas that are interchangeable and often morph into a larger idea, but very rarely do I drop the whole idea completely. Now if were talking half the script after I've written - that's different - I'm known to do that every now and again.

Quoted Text Another approach would be more along the lines of saturant thinking, like dropping a paper towel on a puppy piddle: multiple piddle points begin, then all saturate out to connect together into a whole. By this method you rough out a beginning, middle and end plus however many supporting rough details you have - while your fire is burning! Your infamous 10 to 20 pages. Later, you send your thoughts to work on the bits and pieces in between until the story fills in. Tweak it, bend it, rerun it until it's functional. Kill the beast. Chop off it's limbs and head. Gut it. Take a break. Go to work on breaking down it's individual parts until the whole is processed. Starting at the nose and working your way to the tail explains why you "creatively fatigue" at somewhere around the shoulders, the 10-20 pg point. Hardly edible.

Actually, I very rarely (hence my misplacement of 'usually') creatively fatigue.  I have quite a few ideas, but as anyone with a short attention span, I tend to work on multiple stories or ideas at once - I've slowed in that capacity only focusing on one idea at a time and it's help not only with my writing, but ability to focus more effective, thus making my idea and story flow out more efficiently.  In fact with my western I actually have the whole story figured out.  Though I think this is based on the freshness of the idea and the fact that I refuse to let anything get in the way and my extra free time has opened up the opportunity to write more frequently giving me less time to second guess myself - I think I'll save that for when the script is completed and when it is critiqued and/or ripped to shreds

The only real script in which I have creatively fatigued per se is Dreams of Reality, but that's because it's my very first idea, therefore my pride and joy and if I feel it's not perfect it will not see the light of day.  That's not to say my other scripts are not or will not be as good or better. Who knows my western could be ten times better (in terms of writing style and visuals, etc.) than Dreams of Reality and DOR once complete may be a utter waste of time and a boring uninteresting pile of manure. Of course I would hope it's a little better than manure - for ten years of work.  

I did used to work the way of getting easily burned out - I came up with a title and tried to put an idea with it that made sense.  Nine out ten times - I had to rename the script to fit the idea.  

Now, I use outlines, come with basic plot - beginning, end and middle - make notes of important scenes, but also try and let the story flow and unfold as naturally as possible - and this approach has kept that fire burning as Ray puts it   Of course every now and then I will get a moment or two of "Ooh look a shiny object" and have to refocus myself in my writing