Your boss can't go looking through your medical records. It's a Hipa violation, and there would be computer records of him doing that, if he did.
I know an OR nurse who gets Baker Acted often and still works as a nurse.
You have to get help. You can't do it alone. You are an addict. I give you credit for even functioning as well as you do with all that in your system. Be honest with your doctors and do whatever you need to do to get yourself well.
Thoughts and prayers for you.