I get where you're coming from, I'm sure there's a lot of people facing this issue who can relate.
I relate because I'm feeling the deadline approach already, even though the jam just started. Since I'm using a trial version of the RPG maker MV software, and it's coming towards the end, the 10-day jam kind of translates in my case as a 5-day timer, which is a little infuriating. On the flip side, knowing I have less time, it motivates me to push harder in the time that I do have, so I got quite a bit of work down in 2 days. I'm essentially making every day count, because I really like the idea I'm going with and want to make this story happen.
Point I'm trying to make is, try finding what motivates you to keep going. Why did you join the jam in the first place? Despite what did you join it, even? What do you love about your project? Use that to fuel your energy, and you should be good to go :)