Please don't blame yourself for your sister's death, I don't think she would have wanted you to do that. I am so sorry for your loss
I also don't think she would want you to cut your own life short to be with her, either. I'm sure, where ever our souls go after we pass, she is watching over you and encouraging you to live and embrace life and to find joy in it.
I sure do wish I could scoop you up and hug you so tightly, I really do.
Hang in there. Life is worth living. Give yourself permission to live. I'm sure your sister would want that.
Hugs