Hello new to the site... found it when googling my symptoms, and while I am not glad to find other people are suffering with this, I am glad to know I am not alone.
I've had migraines since I was a child and hashimotos thyroid. suddenly at the age of 36, found myself having these "panic attacks". Went from being very independent ( driving cross country by myself, living, working on my own most of my life) to being terrified of driving, after this happened several times while driving. like some of you mentioned, it also happens, inexplicably, in situations that never bothered me before, like walking through the grocery store or walmart (so I'm not the only one who finds the glossy floors, bright lights and sensory overload difficult!) or talking to someone.
I never had social anxiety and have good inter-personal skills. But since this started happening, sometimes I will be talking to someone and suddenly, i get that lightheaded "whoosh" followed by heart pounding, legs/hands shaking, feel like I am about to pass out. I relate to person who talked about this happending when he tells a punch line to a joke. these are not situations which used to cause me anxiety. and the anxiety i feel now is mostly about being scared that it will happen and I will pass out and be embarassed, happen when i am driving or alone. sometimes i can push through it, try slowing down, breathing, and get through. sometimes this does not work and I have to get away fast. on many occasions I've been in the grocery store, felt fine, not anxious, and all of a sudden - whoosh! the dizzyness/heart pounding starts and I just have to leave my cart and go. the worst is the car. lately I wont drive anywhere other than around town (no highways) because to have this happen while you are driving is terrifying. several times i've had to pull into a gas station and wait for it to pass. twice it didn't pass, and I had to call someone to come and get me. i've been on a highway where there was nowhere to pull off, not even a shoulder - and that was the worst feeling in the world!
I've had almost everything checked out, blood sugar, heart, ENT, you name it. i do get migraines and have thyroid issues, but these are relatively under control and I've had them almost my entire life.
glad to find a place where people won't think I am just crazy or weak. i've been thru a lot in my life and have been a very independent, competent person. the worst part of this is the feeling that is not under my control, like I can keep myself calm and together and keep making myself push thru and do what i need to get done, and bam- it just comes out of nowhere.