Oh dear you sound like you've really got the "heebie jeebies".
I was put with a Counsellor prior to diagnosis at Breastscreen and her advice was whenever you start to feel overwhelmed start to pat yourself down, pat your legs and pat your arms and whilst you are doing this you are saying yes this is me and it is bringing you into the now and helping you to calm and breathe.
Wishing you well with the Counsellor and hopefully some restful thoughts will result after this visit or further visits.
Take care and remember everyone on here at some stage has felt similar