sleepy schnauzer - is this normal?

by Toni
(USA)

My 2.5 year old neutered female mini-schnauzer has been sleeping a lot. She will sleep from 9pm at night to 9 or 10 in the morning, and then sleep most of the day until I walk her. She can go 12-15 hours at night without peeing and only drinks about 6 oz of water a day (I give her fresh filtered water daily). I feed her one of the most expensive dog foods (canned and kibbles) and take her for regular vet visits. Since her last annual visit a month ago (she go the 4-in-1 annual shot (distemper, lepto, para, corona shot) and has been acting strangely ever since. She will sit and stare at me and acts very listless and weird. Is this some kind of reaction to the shot? She used to get up with me at 6am, but now I have to drag her out of bed at 9 or 10am to put her out to pee (sometimes she walks around and doesn't pee even then). The only time she comes to life is when we walk and then she gallops and runs the entire mile. My vet says she is a healthy dog, but I am concerned about her.