Im actually starting to feel really really depressed, can someone plz answer this???!!!?

ok so my final year in high school was really good, i Had loads of friends but they were friends of 2 years since i skipped 4th yr, so anyway i didn't get what i wanted in my final results so now im repeating, but at home ie. getting grinds and things. but now none of my friends answer my texts or calls its like i never knew them, like they all went out new years, b-days etc and didn't even invite me. i would find out from pictures on facebook etc. like i really don't get it? is it just cause im repeating and there in college now? or what? like im a high Achiever & i don't like getting any results and then saying well they'll do, but some of them aren't. i'm sooo confused! btw im 18 and most of them are 19 and 18 too. like i mean i was friends with my whole year! i had my 18th bday in october and they all came out hat'ss actually the last time i've seen any of them. i feel just depressed, and hurt by the fact that they so called themselves friends and i believed that. i reallydon't't know what to do. whenever i think about this i end up crying because you know i'm no 10year old who can go and get new friends just like that; i live in a small town, so where ever i go there's a 50/50 chance i see one of them. please help me and tell me why they might have done this? thanks in advance for taking the time to read this! thanks again.. btw im a really loyal friend and have been there for all of them when other ppl would say they're too busy to talk or anything and i'm known for that but i just dont know.