love cut short

ok, i was dating this guy and i found out one of his best friends liked me. a couple of weeks after finding this out the guy i was dating and i had a fight and broke up. i went to his friend for comfort... fell in love with him... and we ended up dating. everything was perfect until one Friday when we went to a school dance. he seemed fine but i talked to him 2 days after and i could tell something was wrong so i asked him. he said he was just thinking about us. i asked if it was good or bad. he said bad... i asked if he was going to break up with me, he said idk. the next 3 days at school he wouldn't talk to me, he wouldn't even look at me... then finely he broke up with me. all he said was "i am" and walked away. no goodbye hug or anything. i was mad at the time but a couple of days later it finely came to me that i had lost the best thing in my life. iv been in love with him ever since. hes spoken about 4 sentences to me since then. its been 4 months... what am i supposed to do? what did i do wrong in the first place? how did his feelings for me cut off sooo easily? why cant we at least be freinds again? i need help!!!!