Mom passed away a couple days ago, how long will i feel this sad?

15 years old, i used to have the perfect family but my mom started drinking and i ended up in a foster home. i tried to save her so many times, but i remember being little and her needing to be rrushed to the hospital because her liver was so bad but now i look back and i look at our messeges between each toher trying to set up visits but she would show up drunk and i didnt know what to do but i was so mean to her and now i feel horrible i thought i was helping her, she went to treatment so many times and right before she got really sick she was sober for 3months and was so proud becausee she went to AA but then she ended up in the hospital and i didnt know what to do. and she was in there for 5 months and she contracted a virus called ensuphulitus which attacks your brain and suffered from brain damage and memroy loss. i hated being with her in public but now looking back i feel horrible and sart cryiung. after she got out of ICU but her liver was so bad that she went into liver failure and the doctors said ther ewas nothing mroe they could do, her kidneys were failing now and she could talk to us, she was in a coma. she would open ehr eyes occasionly but she was moved to hospice last week. and i gave her a rock with 2 bears in it and it says i love you and iu gave it to her when i was 5 but then she gave it back to me and so i gave it to her the day she passed then later when she passed she was holding it.i just remember so many memories, camping, skating competitiions, singing in the car, vacations, and so much more. everyone tells me how much she loved me and i love ehr so much but i dont even know. she alwasy tried to get ahold of me but i never answered or gave her one word answers and before she went into a coma she told my step dad (i dont knoe my dad ) that she hopes i forgive her for ruining my life. and now i miss her so much and i cry everyday at least 8 times. i miss her so much and we had people staying with up and we made a shrine for my mom and the rock was there but then the 3 year old girl took it and put it somwhere, im so upset i dont know what to do. everyone is asking me if im okay and there therre for me. i miss her so much, before she passed i told her i forgave her and i hope she forgives me for being so horrible and how she deserved a better kid then me. but i look at pictures and miss her so much, i think how this wasnt supposed to happen, i love her so much but i was so horrible, and she tried so hard to get me back, and my step dad is a mess and i want to help him but i dont know how because i just cry. i want her back, any one please help me get through this. i miss her so so so much and i wish i couldve tried harder to save her and spend everyday with her loving her. just someone tell me how long im going to feel like this. i couldve saved her i tried so hard. but now shes gone forever.