Blocked

I'm working on this story for class (my first in years. I've been doing the poetry in creative writing classes for the past eight years) and I'm blocked. It's a metaphor for my own fears of a cancer remission about a guy who has a successful surgery to remove a tumor, and the tumor continues to grow and kill from outside of the patient's body. But I'm stuck at the last act. I don't know whether I'm just too stressed from this weeks events, or too unsure of my prose to finish it and get it out for criticism (deadline for this go-around in class is tomorrow at noon).

I'm thinking it's probably a little bit of both. Obviously I'm stressed and have a lot on my mind right now, but I don't think it's wholly blocking my ability to write. I do need to shut everything out for a couple hours tonight though and get this story finished.