I need some help easy 10 pts please help?

I'm 15 and recently things have been wrong and I don't no how to deal with them. I met this guy in february and hes liked me since. I told him i ddnt want a relationship until after school so he waited until june. We started going out then. We've liked eachother and been super close all feb-june and he said i love you. it was the first time both of us have ever said it too anyone. it was special and meaningful. We really trusted eachother and told eachothr everything and were together all of june. thn at the end of june we did stuff. not but other stuff. thn he wnt on vacation awhile later when he came bak it was all fine but i had personal issues going on in my life and he nvr rlly helped me thru thm and always made me feel bad about thm without noing it. thn at the end of august i met an old friend and we started liking eachothr but i stayed with my bf bc i cared about him and new it was rght thn a week later my bf broke up with me and was nasty about it not even a week later he had a new gf which crushed me even worse thn i already was. 3 weeks l8r he starts telling ppl in my grade (10th) all the stuff we did while we wr together calling me a slutt and easy. My friends have been sticking up for me but its making it worse and I really don't no wat to do im so crushed. and im so upset with myself for letting the othr guy who was nice to me at the end of august go. i really am so lost and crushed to pieces any advice