URGENT HELP NEEDED !!! WITH MY RABBIT !!?

Although it is possible that your rabbit is depressed, it is possible that there is a medical reason for his behavior. If your guinea pig died and now an animal who shared housing is getting sick, I would be worried about a pathogen ociated with the housing. If it were my pet, I'd take it to the veterinarian to rule out any illness. I would also completely clean out the hutch with a rabbit friendly cleaner and replace all of the bedding and other materials.