I usually make a list of final things to complete, and knock them out one by one. A more robotic approach to plow thru it.  The early part of the project is driven by more "fun" and creativity, so I can't always expect the same at the end. In short, I change my mindset to accommodate a change in motivation. Keep at it!

Remember to play test and have others play it too now that it's so close to production. Then you can figure out what needs done in what order. When I made my game for my first jam I did that and the 2 most popular feedback suggestions were a pause and exit button haha. (Sorry that's not an insult against you I'm sure you're game is great and you did a fantastic job, I more mean it easy to overlook simple things in your own work lol)

Take regular breaks. Go for walks. Meet some friends.

When I was about to finish my last (and first) big game, I didn't do any of those things and it let me into getting sleeping problems and all sorts of other stress related problems.
So take care of yourself.

Aside from that, try to break down your tasks into smaller bits and work on those small things. I have a giant piece of paper with sticky notes on my wall and each note was one task. It helped me to stay on track and stay motivated, because you're constantly removing things.

The last thing: If your project is this close to being done, avoid the temptation of adding completely new stuff to it. Your pile of tasks should decrease with every workday and not grow bigger.

But as I said, take care of yourself, seriously.