2 months means he's still getting used to you. Hiding is normal. Guinea pigs are prey animals and as such are always prone to hide as they feel safer this way. Guinea pigs wheek for different reasons...sometimes because they want food, but there can be other reasons too. Chewing on the cuddle sack is probably fine. Guinea pigs explore their world in large part with their mouths so they taste everything to see if it's food or not. He may be afraid to eat the veg while you're holding him. They take time to get used to eating out of your hand. You could put the veg in his cage for a while, leave him be, and he may eat it. Does he have a cagemate? Guinea pigs are social creatures and really need a guinea pig friend to live with. It also helps them to learn how to be a guinea pig like what's safe to eat, etc. Has your piggy ever been examined by a vet? It's good to have new piggies get a check-up, but even more important if you have any concerns. On the main page of The Guinea Pig Forum there are alot of great guides with useful info for new owners. You may want to give them a read.