I think I need help.

I am losing my mind. I am hurting so bad. My ex broke up with me 2 weeks ago today because he said I wasn't the one for him. There wasn't anything I didn't do for him. He pulled me off a really rough path and he was everything. I didn't want to trust him or be around him alone when we first met. I didn't open up to him about anything and he finally got me to open up to him. He was everything I have ever wanted to be in a man. I am only 19 and he is 20. I been through a lot and he made me be myself again. The sweet me. He posted a picture of him and a girl on Wednesday 2/18 saying that he can't wait to see her again. I find out they hung out on Valentine's Day. I also find out she is in high school and she is 16. He gave me a necklace on Christmas eve. And I called his mom and asked her can she get it. I can't give it back to him. I don't want to see him. I hate his guts. He keeps leading me on thinking we are going to get back together. On Thursday 2/19 he was all over me. He held my hand asked me to sit with him at dinner. He flirted with me because it was cold and he kept asking me come closer to him to warm him up. The next day he said he didn't mean to lead me on and we aren't getting back together. I am so sick of him doing this to me. He did this Friday 2/13 too. We had a performance and we are lunch before the performance and I was going to sit on the opposite end of the table and he said why ain't going to sit with him. So I sat with him. And he did the same thing then. I am hurting so bad because earlier he posted another picture with her and he was at her house. I hate him. I am so tired of being in pain. Someone please help me. I don't deserve this. I don't. I haven't done anything wrong.