Maggie... welcome. I am sorry you are feeling such pain, but know that there are many who understand your pain and that they will be along to lend support. My addict is my soon to be ex-husband. But, no matter who it is in your life, the pain is very real and similar. Know that you have done a great thing by looking for support. All you can do is take care of you. You can't control your son's behavior. You didn't make him use, you can't make him stop. BUT... you can focus on how you will take care of you and how you will react/respond to the situation.
Keep coming back here and know that you are in my thoughts and prayers. Meetings are great idea and a wonderful step forward. Look for Naranon or Al-anon (lots of times there are not Nar-anon meetings as readily available). You are taking wonderful steps towards sanity and survival.... good for you!
HUGS