I really messed up this time.?

I am the kind of girl who would never get into trouble. My parents and my whole family have always been so proud and all that. I used to know what i wanted. Last friday i ran away from home with some "friends", i got really drunk and i think i was sort of high too. I ended up in a bathroom with a guy i didn't know, i sort of remember what happened. We were making out but i wouldn't let him do anything to me, i treated him like dirt i told him i would never ever be with anyone like him. I really don't know what happened to me i never thought i could act like that. As soon as i could i called my parents and told them i was really sorry and i needed them to pick me up. Of course i am grounded and they are really mad at me. I feel terrible, i had never done anything like that before, i don't know why i didi it and i don't know what to do now. i feel like i'm not worth anything. I also feel betrayed by those who said were my friends, i know i can�t blame them but i just don�t know how to fix this mess. Some othe friends told me not to worry, they say we are young and we can be stupid but that doesn�t make me feel any better. Please i really need help.