I’m no expert, but I would think it’s either something spooked/upset him and he’s on more high alert than normal, or there is some kind of ailment.

I’d worry about ailment first of course so would ask myself is the rabbit eating/drinking/pooping/peeing all normal? If you do regular weigh ins, is the weight within the normal range? Anything off, well I don’t know enough so unless it was an obvious cause, like I changed food and the rabbit hated it I’d hit the vet office.

If all things look otherwise normal health wise I would assume something happened to put the rabbit on guard. If there is something new going on in the household, it’s likely that-any new pets, new vacuum or other noise maker (my bird hates our new vacuum, but was fine with our old one) Any guests? Could anything of happened with another family member? Accidentally spooked him? Even a next door neighbor with a new dog?

If something got him spooked it may just take a few before he’s willing to relax and let his guard back down.

Good luck and hopefully it’s just some little thing that will pass shortly.

I wouldn’t worry about it. Most likely he’s annoyed at he change in his space. My buns have gone through periods where they flop more or less. Now that they are older (almost 8) they are lazy but hardly ever flop while out anymore.

My goodness that is a handsome bunny!
My bunnies flop less when it’s chilly.

So cute! Looks like a little stuffed lion!