TL, I am sorry, but you are doing all of the right things in trying to stay strong, let go and be kind to yourself.
Sometimes, when my difficult child keeps on doing dumb and dumber stuff, it helps me let go more. He's not "kind of doing better" which gets me confused about my role---do I help when asked or not?
When he is completely off the rails, it is clear that I don't need to do anything at all.
I can't fix addiction. I can't fix stupid. I can't fix bad and badder decisions. I can't even fix his one step forward and two steps back progress, when it occurs.
I just need to stand back and stand down and let him walk his path. Whatever it is.
Fear gets in the way, and when it does, I have to get busy doing physical things, like working in the yard, scrubbing that everlasting kitchen floor and then taking a nap and reading a good book.
I have to feel the fear, but not act on it. Your fear won't kill you, TL, so just let it flow over and through you if you need to. Lie down and cry, then rest, then get up and dump your thoughts and feelings into a journal. Those small steps will help you when the fear and sadness and despair take over.
We are here for you. You have done all you can do, for now. Let it go as best you can. Warm hugs.
