Im so lonely. i feel so alone?

i used to be really close to my oldest sister ill call her alessia. i have a middle sister melissa but we were not close atall. when me and my mom went on a trip for 3 weeks and we came back alessia was all packed and moved out to her brandnew boyfriends house it broke my moms heart, my mom still cries for her and its been 3 years. she still keeps in touch but has changed. to a WHOLE other person. my mom got depressed over her, and i didnt feel anything. i was numb i woul miss her but was ok. i dont know why or how or whatever it was just. then for these past 3 years ive been crying for my dead brothers because i needed somebody i guess i got over them now. ive grown closer to my sister melissa but im scared she will leave me ive become so close to her that if she leaves my heart would break. i think i will die. im sooooo afraid of being alone , i hve trouble letting people in and im afraid ill lose my mom and it hurts to say this but i keep on hurting her and i cant stop i just get so angry sometimes. i think i get it from my dads side of the family , they are evil. my grandfather d his dead brothers wife. my grandma watched her blind dad fall to the floor and get all bloody and not help him left him there on the floor and said if she helps him she wants money. the used ot beat and lock my mom up and not feed her and when i was a baby i was about to get runover becase my grandma left me on the streets then told my parents that i was there and she didnt pick me. i could go on forever.... and im inlove with a guy who is inlove with my goodfriend who is a backstabber but i still deal with her because she helps me with some stuff. she went out with him and might get back together, but there right not me. i just have feelings for him.....i feel so isolated and cold .....and its sooooo hard to make friends for meeeee cuz i cant express.nothing will come out im scared of admitting the truth barely brings myself to cry and lonely and hurt. yet i have loving parents a good house and good clothes and make-up and gets whatever i want. GOD JESUS CHRIST PLEASE HELP ME <3