welcome jacksdaughter. you have truly come to the right place. hang around here and people will be sharing their ESH in a situation just as yours.
If you are a reader, there are many good stickies at the top of this forum with also a list of books that many of us have found to be not only helpful but lifesavers as well.
As far as your being surprised about the extent of his problem, that is very common. The nature of addiction is to hide the details of it. Many of us have had to come to the conclusion that our loved one has a drug/alcohol problem because of the signs and symptoms only. I myself have not seen my AS partake of drugs/alcohol all that much - in fact, my oldest son really cannot believe that his younger brother has a drug or alcohol problem - he's pretty sure that his brother as a problem with laziness or immaturity. But my conclusion that this AS has a problem comes from all the signs and symptoms that i have seen.
Stick around not only for yourself but for the sake of your son and the rest of your family. There's a lot of ESH (experience, strength, hope) here for you. The feelings you are experiencing right now are very normal - we have all had them. But you will find that they will become less large in your life as time goes by and especially as you embrace your own recovery - trust me on that one.
Keep coming back. It works if you work it.