Anxiety attacks. To fix myself.

Hi, I broke up with a girl recently (a week back). She used me for money and other personal needs and left me when she found a better option. We were together for like 1.5 years. She was my first love and I loved her like anything. Helped her n her family with everything possible. I cannot explain in words what I felt for her and did for her. Her family n my family knew about us and was discussing about our marriage. But now I know that she wasn't a good person and was a gold digger. But the breakup happened so fast (in like couple of days) that I didn't even got to prepare myself and didn't even got a proper closure from her. I have so much rage and frustration in me for trusting such a pathetic person which I cannot let out. I cannot concentrate on my daily work. I know it is useless to cry for such a person, in fact I should be happy about it but I just can't forget the betrayal she n her gold digger family did to me. Please suggest me something to fix myself.