totally understand. I would Definitely take the next week to rest like you said. I am sorry it is all a roller coaster for you and I don't know why you are putting yourself through this, as you said. I can relate, I have a similar situation as far as not letting a bad situation go, it's like I keep gravitating back to it?
Sigh. I wish I had more advice for you. Listen to your body, as much as you don't want to. You don't want to risk losing your new job by not being in the mental shape to even start.
GOOD LUCK. Please rest. (easier said than done.)