Dan - I don't know you but from your posts I can say your story is an exact duplicate of a friend of mine's ... He's in DEEP and I fear for his life everyday. But, he isn't ready. He will know when he is, hopefully before it is too late, and you will too.
You have already taken the first step in recognizing you have an issue with drugs and alcohol - when your time comes to face it and conquer we are all here to support you.
Wishing you the best on your personal journey