How long have you had this bunny? And since when is the change?
It’s changes not any one thing that you should look for. Changes in normal behavior, coat, eye, skin etc-are your indicators for illness. They are such individuals that what one does is not what another one will. For instance, Kahlua has large lymph nodes…so if I were to take her to a vet that didn’t know her they may think she’s fighting an infection, but really that’s just her. A change in the size would be an indication but not their size in general.
Or Rupert-some people may think he’s comatose or ill, but really-he just likes to eat while laying down he’s sooo lazy
And that’s normal for him. So it all depends on what is normal for your bunny.
I definitely agree with the vet that as long as he’s eating and pooping he’s probably fine, however if what you listed is a change then there could be cause for concern…perhaps a checkup is in order. They should have an annual exam at any rate so it wouldn’t hurt and may reduce your stress.