Vet ruled out everything serious. All his vitals check out. You should feel really bad for him though, he had to have a rectal temp taken AND a prostate exam.
All the things up my dog's bum. Poor sod.
So, likely bladder infection or less likely, crystals. Getting a urine sample tomorrow morning and taking it to the vet on our morning walk. Love that the vet is so close! He sent me home with a week of antibiotics so we can start him on them anyway, since it's likely an infection.
In positive news, Finn is an even 45lbs and all muscle. Vet commented that he's in great shape, and everything looks amazing. Yay!