Dog Collar

Hi Everybody! I was just given a puppy Beagle who is two months and a half,,since I put  a dog collar on him, he gets depressed. It  is  very lightweight and even it doesn’t any tags. He doesn’t want to eat or play while he is wearing it.. he looks so down. Should I go on to put the collar on him?  or  Any ideas ?  he is still a puppy ,,I’m very troubled  about him..