I started a whole different project like 7-10 days into Prep in 2019 and not only finished Prep, but won NaNo as well! I think I did skip some of the exercises I'd already done and just thought about them in the shower and such if I didn't have time to redo them for the new story, but I don't recall for sure. I would say that you should consider spending free time like in the car, on the toilet, in the shower, etc. pondering different parts of the plot so you can at least have ideas in your head. Preferably have a notebook or know how to record things on your phone, so you can get the very best ones down somewhere.

You got this! I believe in you!