i'm exactly like you. exactly. it's so hard, i know =[. i don't know if it'll change, i'm sorry. i've been like this all my life. (i'm 15). i probably won't be able to change, but i really hope you do. just wanted to let you know that you're not alone with this..
you shouldn't have taken it to the heart.. it's not that big a deal. if that girl said it to embarrass you then i understand why you feel that way. but you're making it seem like it's wrong to be a lesbian..that's why i asked 'why get so offended?' before.
you're only going to be 19. you don't have to be in a relationship now or anytime soon. you're still young. you have your whole life to live. focus on the good things in life. and don't worry, you're not alone.