Esme…
Ask yourself what is the worst thing that would happen to you if others knew your secret?
I think your doctor ought to know, just for your own sake. They need all the history of their patients to do their job. Fill his/her in.
As to your neighbors, people at Church, or at work, maybe/maybe not. Some people will use information like that as a weapon against you. Not most people, but use best judgment in whom you confide.
I am an alcoholic, and I like you was strung out on crank as a younger man. I am also a member of Alcoholics Anonymous. I am not suggesting you show up at a meeting, unless of course, you are romancing the old life that is. But one of the things I learned there was “We are as sick as our secrets.”
If carrying this dark secret about your past around is weighing you down, and it looks like it is, set your burden down. Like I said, what is the worst that could happen?
The people who love you will still love you, and the ones that don’t still won’t. In all probability the only thing that will change is your peace of mind will improve.
Richard