I can understand this. I don't know that I've been having such an issue with staying focused. More like, I think I probably should've planned better. This is my first jam though and I'm definitely a beginner with Unity and game dev in general. I definitely overdid it the other night. Stayed up until 2AM working on stuff, but it's been pretty discouraging actually because I don't feel like I have a lot done despite this. I figured I'd go to bed early today and come at it fresh tomorrow.
I more or less have been following what I know as well, too. I think that alone is enough for me this game jam. I'm trying some slight new things but for the most part I'm keeping it safe because I don't think I could manage anything more. Hopefully, I'll be able to complete a submission by the end.
But yeah, not sure this really helps or not, I guess I'm just giving you my own experience so far. Good luck all the same though!