Sorry to hear that you were not having a good day... take comfort that setbacks are part of recovery process too.
i had a couple of tough days too recently...feeling fear, depressed, getting paranoid over symptoms and stuff... it was tiring .
decided to invest in some online books/programme and am starting therapy again soon. its a worth a try. reading up has been helping quite a bit. do some light stretching here and there to loosen up the tense feelings while reading perhaps?
perhaps u'd like to consider therapy too. its the fear that we need to manage... easier said than done sometimes 
but just keep trying, invest in a good book that would assist along the way, have the book with u especially when u are alone, or make little notes from a good self-help book that would be convenient to take out and read when you are out alone and get those symptoms....and try therapy if you can... as for good nutrition i guess you are doing well already in that area, keep it up..
take solace that a/p is a treateable condition, tats what i read in many online articles/self help books too, its gives hope :) but depending on how long u been having it, it takes patience, practice, setbacks here and there..