How do i stop being so self conscious when my bf holds me?

k so my bf has this new like obsession with holding me and its totally sweet, but every time he does my mind just starts going crazy telling me that while he's holding me hes thinking I'm fat and i end up pushing him away. i can tell that it's really getting to him but I'm just so self conscious i have no idea what i can do. all i want is to be able to snuggle up with him and be comfortable but i just... cant. please help :(