What exactly has your son done that you consider selfish and hurtful, tarring and feathering you, hateful? It is hard to know if your reaction is proportional to the actual offenses or if this is your perception and emotional reaction that might be somewhat out of proportion.

I say this because you say you are having panic attacks and talk about being brought to your knees, and I know your son is about to get married and you don't like his fiancee. So, it seems in the realm of possibilities that perhaps your reaction is complicated by the idea of your son moving on with his own life and that you feel abandoned which can trigger very intense reactions like panic attacks and feelings of persecution for some people.

Do you have a therapist who you can talk through these intense emotional reactions with? If your son is pulling away when you are reacting this way, it may be because he finds your emotional reactions far too intense or perhaps manipulative. I'm not saying they are, but that may be his take on those reactions.