when i brought lenny home from being neutered, the pain meds really did a number on him. he was limp as a noodle. it was actually pretty funny, he would be sitting up and then gradually his head would start to bob and his eyes would close, and then once his nose touched the ground, he'd spring back up again all alert and then gradually start to fade again…
good luck to you trying to keep mia from jumping around... not easy with a B!