I was in a similar situation a long time ago and ended up having a breakdown. My main advice is to focus on whatever is absolutely necessary and don't go in without an exit strategy; you surely don't absolutely need to do all of it, weigh the benefits against how stressful it is.

I wish I had a tip for how to actually go through with doing it and doing it more effectively, but that mostly lies on being in the right headspace to learn new concepts which is hard to do when under pressure.

Edit: oh yeah and also sleep well