RN I am sending hugs to you. Trust me when I tell you that there were months I could not go out in public without hiding my head in case any of our friends/neighbors would see me and ask about my daughter. I found myself tearing up when I walked into stores that she and use to shop in. I had to call my older daughter once and have her meet me at the mall to return something I bought her, I simply couldn't walk into the store. I was in a mourning period.
It will take you time to accept that your son has a problem that you did not create, you cannot control it and you cannot cure it. It is not your fault. He doesn't yet realize what will happen if he continues this road. Remember he is still very young. He is thinking only for the moment. Until he surrenders to the fact that drug/alcohol are more powerful than him he will fight it. He probably sees his friends doing the same as he is and they are fine.
The only thing that helped me was time and my support groups/people. They understood what we were living because they lived it also. When they said they understood, I knew they did. There was no judgement or finger pointing. And what I found was the more I shared, the more I realized that we were not alone.
Enjoy your pizza (and maybe a glass of wine) with your husband. Make sure you keep your connection with him strong. We had to find thing to laugh about in the middle of our crying. There is hope RN, I have seen it.