Welcome and I’m sorry for your loss. Losing a parent must be incredibly difficult. Try to think of what your dad would have wanted for you. Your parents helped you to get sober once before. He would want you to be happy and healthy. There are lots of resources to help you get through the initial withdrawal. Just take it one day at a time.
Check out this thread for a list of resources for staying sober:
It also wouldn’t be a bad idea to speak with a grief counselor if you have the means. It’s important to learn how to manage emotions during the grieving process. Sobriety will allow you to move past your grief while using will only keep you in your grief. There are a lot of empathetic, non-judgmental people here on the forum. You are in the right place. Thank you for sharing your story. We will try to support you to the best of our ability during this difficult time.