Work on something really new too you, if you need a break take one (duh). It really helps to use background music/podcasts, you could even listen to videos about game dev in the background! If you find the project not motivating, try something else, or work on art for a bit, or whatever. Don't spend all you time doing this (unless your in it for the money) and focus on the aspects of game dev you like most. Try to do an additional challenge, like you can't use external tools to make a game. Take breaks often. If you see your mood shifting towards stressed but done, you could even take a day off, and leave it up to a friend to help with art.
If making games in a time frame is stressing you out, just know this: It doesn't matter, you can use a broken game as your entry, its for fun.
tldr; game dev audio in background, take breaks, and focus on what you like.