I'm so sorry you are going through this, justjo. I understand how it feels, trust me. The thing is...least is right. You drinking is not going to make anything better and could make things so much worse. I know how unfair it all seems, but I'm sure your sister would want you to take care of yourself. She is no longer suffering and soon, your memories will be of the happy times you had together.
Perhaps finding a grief counselor or group would help. Just talking to people who have been exactly where you are might help. They could make suggestions on how to deal with the pain you are feeling and move on with your life.
It's just a suggestion. In any case, please, stop drinking and take care of yourself. ((((HUGS))))