I know you have and all of it looks great. So all we now know is that a squirrel on a good diet had one reported instance of blood coming from the anus, then later stopped eating and wanted to sleep all the time. That just isn't enough info to do anything but make wild guesses. When I say "more info" I mean like bloodwork and x-rays to see if there is something going on in his intestines.
Has he come out yet? Have you tried to offer him anything by hand or even offer water by syringe?
And if you will not provide even a general idea of where you are located there is really no way for anyone to help you with SAFE vet recommendations...