Jaquta has given you some fine advice..I would only add that diet pills might actually be dangerous for you with those other medications...they are all stimulants of one kind or another.
that phrase is used as a descriptor rather than a diagnosis. It may mean nothing more than your son is difficult to talk to because he won't verbalize what he is thinking. I think you should concentrate on the anxiety and depression, both of which make him turn inward, and see about some psychotherapy as well as medication.
If you go to a thyroid specialist, that doctor can order some more sophisticated tests and may be able to tell you if you are an over reactor to that level of thyroid. It is worth a try. And many antidepressants do make you more jittery because they are stimulants, so ask your doctor about trying another antidepressant.
I know brain zaps can last for a while, but usually go away. I think you might be making it last longer by using pot.....you are stirring up all of the same chemicals in your brain when you smoke pot....