i'm really sorry you're going through this. i've had a lot of your symptoms. they are very frightening, but they will pass. are your symptoms worse since taking the drugs? did you have anxiety all the time before?
i don't think you have a nerve problem, i think you have a parasite problem! you're descriptions sound very similar to what happened to me. and i wasn't losing my mind..but they make you feel so bad, actually, i had a period of time i was very ill and at the same time felt like any moment i might lose it. i hope you are not feeling this sick as well.
doctors that say you are obsessed with parasites DON'T know what it is have it, and all that happens because of it. they profoundly effect physical and mental state...and not mental state as reaction to them, i mean they will themselves, effect your emotions and congitive ability.