How do I get over this?

Hi everyone I am new here. I have just been broken up with recently and I can't shake it. The guy I was in a relationship with I believe was a narcissist. He broke up with me for some other girl and now I am left trying to pick up the pieces. I feel like he sucked everything out of me. He always put me down and made me feel like crap. Everything was always about him, but the problem is I still miss him and I don't know why. I feel like I was replaced just like that, like I was nothing. I feel like I was just thrown away. I don't understand why I feel so conflicted, it is like my brain is saying just get over he used you move on but my heart says it misses him. Any suggestions on how I can resolve this conflict and how I can move on?