Oh gods, by all means force it. Put a figurative finger down your figurative throat or squeeze your figurative cheeks together and figuratively do a squat thrust. Take some figurative laxative. That's exactly what you need to do. Poop that damn story out!
Remember that your words are not semiprecious stones. There will be other words, and you'll love those just as much. Copy is just copy. Write until your figurative fingertips bleed, just to get all of the bad writing out of your system as fast as possible.
Ah GuarONtee that'll help. Don't agonize over an individual story til it's done and you're happily polishing it and dreaming of possible markets. Let the disillusionment set in later, when you're subbing to said markets.