When Lola was younger she used to do that ALL the time - it was almost like she didn't realize what her ears were and they would scare her (I put a video below to compare if it's something similar your bun is doing). I also agree if it's a new bun they probably need a check-up - but in my case it was nothing to worry about other than a silly bun getting used to her floppy ears.
ETA: I think you were the one that started the white sludgy pee thread? So if you already have a vet's appt scheduled just start making a list of things to ask them! I always forget things so it helps having that list when you go in!