HK I'm sorry your hurting and struggling with letting go I went through this too when I/he exab broke thing off and immediatly starting dating someone else. Right in front of my face I was broken I really felt my life was over NO one would love me like he did and now someone else is having him. My stomach was sick I was sick.
I spent the 3yrs in our relationship being kinda the caregiver babysitter. Is he using is he gonna use. All my thoughts and focus for 3yrs of my life was ONLY on him. I totally forgot who I was b4 I started dating him. He consumed me I loved him more than any other human on the face of the earth we were gonna be together forever.
When we broke up he told me it was because he didnt want to hold me back in life. What a crock of sh!t I thought how dare u. I only wanted to be with him he wasnt always nice to me and didnt really care about my feelings nor anything else about me. I didnt see it at that time. I wanted him back I wanted to be with him. My health suffered I went from a size 7 to a 0 in no time at all. My stomach was sick and sinking I didnt sleep for what felt like eternity while he was off not suffering with this other woman. HOW DARE HE! I was mad and angry and hurt. When I read your story I could have wrote I really could thats why I sometimes have to stay away it brings me back there.
I had to start throwing myself in other thing to take my mind away from him. Kinda like your doing I was bz all the time. I looked up old friends that I stopped talking to to be with him all the time. I went to college I worked full time. I had to focus on me boy that was hard. As time went on I thought less and less about him and eventually was able to really let go and move on. It was the hardest thing I ever did. In time u will think of him less and less and u will realize how amazing of a person u are it doesnt happen overnight but it will happen I promise u this.
Sorry this is so long I just wanted u to know that u will feel better u will move on.