I've been dragging my feet on finishing Galactic Game for submission. It is not that I don't like the story--I love it. Mostly it is because I have a low energy level and final editing takes concentration! I get off work, come home, nap, do my exercises...flake out or read a book. Next week I increase my work day, so we'll see how that goes. I'm 4.5 weeks post surgery so went back to work a little early. Some days are better than others, and some nights I don't sleep well so there is no point in getting all stressed out about writing progress at this point.
I decided to give myself a break and work on my synopsis for Starlander 2. A few nights ago I had a very visual, memorable dream that added a significant amount to the story...and changed the hero. I am adding it to what I had and then see if I like it.
Just another thought: After I had surgery it took me several weeks to be able to focus enough to write. I also heard the same thing from another writer friend. Good luck! You'll get your motivation back.