I'm really sorry that you had to experience something like that.
I know how it feels to lose someone close to you and I know what you're going through right now.
The best thing to do now is move on, I know it's hard but I've spent over 6 months mourning and it's getting me nowhere.
Try to remember her when she was young and healthy, remember all the good times you had but don't get caught up in the past.
You've already made a good first step by telling the people here, I found that talking about my feelings really helps, if you keep them bottled up it will eat you alive.
Another good thing to do is find an outlet for your emotion, if talking to people isn't enough try writing about your feelings in the form of poetry or just write down how you feel in a journal.
Hoping you feel better soon.