I feel so angry . I got cheated

Okay so I was messing with this boy for a year now and I have feelings for him. We ended in July due to the fact he was talking to another girl. He came back to me and promise it wasn’t even like that and that he misses me. Since I’m a clown and so blinded by him, I fell for it. I let him back in and then two weeks later, I found out he got back with the girl and he drop me like if I was nothing. I wrote paragraphs to him and he blocked me. I feel useless. I feel empty . I feel heartbroken . More than anything, I feel angry. Idk if I should stay quiet and move on with my life and let time do its thing, or fight back like contacting the girl who probably has no idea on who I am like the way I didn’t know about her at first.