What wrong with me I chose bad bestfriends ?

Well my bestfriends hate me just because I got cought smoking now they dont even want to see me and it hurts I helped these guys a lot my friend dave thats 20 I gave him food when he had no money for food and his girlfriend my friend grace shes 19 I got in fights with my family over her I even got kicked out of my moms house for protecting grace later on my family helped her get traing for job I was nice to them I started to open up to them then dave and grace turned their backs on me I thought I did somthing wrong so I relapsed and started to smoke again then I got cought I dont how they found out then they realy started to egnor me one day went to visit them when I got there they look at me with hate and disgust they made me feel really bad then a week ago grace send me a comment on a social site saying she never wants to see me again and that I was going to be nothing in life and that the rest of the gruop hated I got mad and sad I wrote back that I hated her and I called her names also that im goning to do somthing with my life im finishing school and I have a job and both dave and grace never finished school and grace doesnt even have a job then I started to talked to the group they dont hate but they dont like me dave and grace have been saying bad stuff about me to them about me so I started to talk to my old friend jordan and nick and they are still cool with but then I start to think did I ruin our friendship with dave and grace. grace says she doesnt judge but judged me they hurt me bad I gave them all my trust and at the end they backstabed