I think I'm too fat to have sex with anyone new

Basically, I have been chatting with this "new" (we have previously been friends) lad who to be honest, it quite nice but I feel as though I'm pushing him away because I'm embarrassed if he see's me now (because I've put on weight since the last time we met" that he would turn me away (I get anxious about rejection because it just embarrasses me) or tell his friends something like "no I didn't go there because she was HUGE".