To blurt out something like that is unforgiveable, it show lack of respect and downright rudeness to be honest. It should be up to you who you tell and when.
Tom, is it, should be ashamed of himself. And please dont say you are childish for thinking this because its not childish at all to feel this way about the way he has treated you.
All I can really say is, a true friend would respect your sexuality and except that. It shouldnt make you any less of a friend. Be proud of who you are and dont let anyone make you feel bad. If they were true friends they would understand and not ostracize for your sexuality