Could it be worms makeing its belly fat?

could it be worms makeing its belly fat i havent seen any in its poop????? but im going to worm it just incase it whines before it goes to the bathroom to like its in pain what could that be .. i dnt have the money to take it to the vet but i cant just leave it there helpless it also has something wrong with its back leg it puts a little bit of pressure on it but not much and like i said i cant afford to take itr to a vet at all should i wrap its leg up?????