I used to do that all the time with my engineering career.....when we had deadlines it wasn't unusual to work 60-80 hour weeks even though most of the time I was able to work them on my schedule unless we had meetings with the military customer. But at the end of pushes like that I would always take a long weekend or take a week off just to catch up on sleep & then gradually get back up to speed at work after that. I was lucky that I worked in a field that allowed for us to take the time off & recooperate after big pushes like that.....but I also never felt guilty because I knew the huge amount of work & the long hours I was doing so I felt like I deserved the time & felt that the company actually owed it to us we we were willing to kill ourselves for them like that.....just glad that the companies I worked for felt the same way I did about it.

Glad you are resting & not feeling guilty....sounds like you will be more than ready for that new position.