I lost my best friend forever </3?

Long story; We had a group of 4 best friends. Sarah, Karley, and Hayden. We did everything together. sat together at lunch. Had sleepovers. We practically lived with each other. We all shared everything with each other. Sarah was in love with a boy, that I liked, but they broke up awhile back. and Karley was in love with me. Hayden had a boyfriend. and me and Sarah were talking about how she was over him. and everything. and then he asked me out (he liked me) and i said if it was okay with Sarah, being a good friend. and she said it was fine. and we had a long conversation about it, she was perfectly fine. and Then Karley found out and said we aren't friends and i was able to convince her i liked her which made her my friend again, (now were fine and she dont like me) but I then Hayden found out and sent me a message saying she was done with me and deleting my number. Sarah said she would make everything better when i told her about what Hayden said. Well now they both hate me. I immediately broke up with him. and i still like him. its been a week and she still hasnt forgiven me. Everyones saying i should give her time. i made a lot of mistakes on my part; but i realized them and i wanna make everything better, i wanna change everything. does anyone know what i can do to make this better/.? Im so depressed// going through a lot. Im going back to cutting. and theirs no family for me to talk with, my mom abused me and i live with my sister. shes struggleing to keep a job and support me. I dont wanna make her worry more. all i do is make mistakes. Why should i live? theirs no point. **** MY LIFE.