Oh my, I just want to hug you. I'm so sorry! I can't imagine your loss and pain.
I don't know if I have any suggestions for you except this: Please try to love yourself as much as your sister loved you, please don't turn to alcohol to soften the pain. It's so dangerous for us now.
Are you in any form of therapy? I feel like this is a really big thing and maybe too big for me to come up with any helpful words or ideas. Dealing with loss and grief like this, even for people who aren't dealing with what we are, is already so hard. Of course you are struggling and feeling like you are going to drown in the pain. Of course you are turning to other things because our old standby of food for Comfort is gone. I have so much compassion for you, I wish I could help you.
Do you have someone to talk to, you said your sister was your best friend, do you have another person in your life you can talk to? I want you to know you can message me, if you need an encouraging word or just want to chat.