Our prayers are with you. Please try to get to the meeting tonight. It will help you keep your sanity. I am not good with strangers either, however, at the meetings I've been to you don't have to talk if you don't want to. I've gained a lot just by listening and reading the material.
Those who care about you will not judge you because of your son's actions.
This is not your fault. Remember the three Cs -- You did not Cause this, you can not Control it, and you can not Cure it.
Your son is an adult. The fact that he is storing "clean" urine, tells me that he knew this was coming.
We have all been there and we're here for you!