My 2-year-old rabbit suddenly started peeing on the corners of his playpen and getting in a bun loaf in random spots he never lays on. He's acting unnaturally and even let me half pick him, up, which he never usually does. I think he's in pain(because he was on his stomach)and set him in the litter box to get it all out. He peed a bunch in there while standing still, tail up, nose twitching fast. He nudged away the lavender I offered him. He's now laying in there. What should I do? Did he eat something bad?