Feeling depressed at the end

(Sorry, I realize the text will not have any structure. The site will automatically mash everything up into a wall of text. Something I believe the admin should look into. Let us post Questions that keep a certain structure, like the shared work so it is easier to read such “large” questions.)

I was just wondering if this has happened to anyone else.

I recently managed to type the final full stop to one of my MS (yet again, finished the 6th draft of it). I wrote that ever so sweet and glorious “The End” and leaned back, waiting for waves of excitement to rush over me as they did the first time I typed that little dot that means so much. But I found myself feeling a bit down and depressed.

All of a sudden I started panicking that my work wasn’t not good enough, no wrong, I felt it was useless, all wrong and I should open a draw, through it in and forget it, never show it to anyone. I felt insecure about my work all of a sudden, and to be honest I was a bit shocked. Soon enough depression sunk in and it was visible to everyone that knows me. They complained that I all of a sudden turned moody and bitter.

I am usually a positive person. Some people even complain that I am too much most of the times, always cheerful, able to see the silver lining in any situation and keep smiling like a moron (quoting my friends here), even when things appear to be grim and impossible to deal with.

I always like to find the good in everything, the positive side of things, but when I finished my MS (I believe it is now at the best of my current abilities) depression followed and I am a bit baffled by it.

All it took was about a week of regular coffee with friends and family before I got my confidence back and I returned to my usual annoying self, always looking to crack a joke and make people laugh. But the shadow of that feeling is still hovering over me. I keep wondering why it happened, why the sudden relapse of emotions.

So my question is this. Did this or something similar ever happen to you? Is it usual for this to happen? How did you deal with it? What do you think it was?