Is he neutered? Is he shedding right now?
Both un-neutered and neutered bunnies can get March hare craziness this time of year (if you’re in the Northen hemisphere that is). It’s worse in un-neutered bunnies though. An increase in the amount of light influences the production and excretion of many hormones, not just sex hormones.
Pooping strings of poop means he has ingested hair, and that’s not ideal. More hay and more water is the best thing to keep the intestines in good working otder, plus you should brush him every day if he’s molting. If he gets veggies you can serve them dripping wet so he gets extra fluids.
Is his appetite still good? Obsessiveness about treats and pellets is very normal rabbit behavior. I don’t know of any rabbit illness that involves an increase in appetite, but the opposite is a very important sign of sth being wrong.
Rabbits have a blind spot right in front of their noses, so they can’t see a treat on the floor in front of them, they have to find it with their sense of smell. It can look a bit pathetic when they can’t find what’s right there, but it’s normal. The have a very broad visual field, but they see much better from the side than from straight ahead.