How can i stop worrying about him and worry about myself? If uve been through a bad break up plz give advice!?

My ex and I broke up a month and a half ago, luckily i havent made a pathetic *** of myself by begging for him back or haring him, as far as he knows I am fine without him but Im not. We broke up last year and he started seeing someone else and he straight out told the girl to be more like me and talked about me all the time. I have no doubt he isnt taking this too well either but his way of moving on is to replace me fast. He treated me so badly in so many ways that i didnt deserve. I CANT let myself go back to that but Im lost, i dont know who i am, i have no self worth because I couldnt make him love me enough. How can I get all these thoughts of him out of my head and let go of all of this resentment. I am so tired of hearing myself talk about it and my poor friends and family have to be getting tired too. I cant get into another relationship feeling the way i do now. Im vulnerable and not a whole person right now. All i think about is him, how can I JUST STOP IT??? I have tons of my own issues to worry about and i worry enough about him and alla his enough for the both of us. I just want to be happy.