yes, i can totally relate. and sometimes like u the best thing for me to do is sit in a dark room doing nothing, no noise. sometimes it's hard to talk even. i find places like walmart, etc can cause to be too much stimuli. i can avoid sometimes a full overload by leaving the store. if i'm like this i don't drive. pretty much stay at home. maybe get on the phone if i can. takes my mind off it.
sounds like you had a full blown anxiety attack. my T said it starts with free floating anxiety. then manifests the symptoms. i take an extrra anxiety pill, pdoc said ok, and it helps some too but not totally. it's like the panic attack has a mind of it's own once it starts. i have less episodes now partially knowing the signs and taking measures to minimize the attack.
sounds like you were on the right track to calm down.
hope you feel better today.