Hi mally, we are behind you and beside you all the way with this. Years ago when I suffered (for some time) it just wasn't "done" to talk about things like this - I wish it had been, I too felt completely alone in it, and felt I was losing the plot. It's such a scary thing, even though you know it passes - but it feels like an eternity.
Medication helped me, and later, a sense of self wanting not to be ruled by this for the rest of my days. I still get the odd little symptom, and occasional agoraphobia under certain circumstances, but overall I've been clear for probably 20 years now.
So glad you came on here to talk about it - we know what you go through, and we're with you.