You are definately NOT alone. I remember when I first started having panic attacks as a teenager the more people I told, the more people came forward and admitted they had the same thing happen to them.
My husband is also on Meds (different then I take) for the same type of problems and my own brother does not leave the house for the same type of problems. With my brother though, he won't take meds, so he really hasn't made any progress. I found out later in life that there are a bunch of people on either side of my family that suffer from problems like this. Of course my parents never mentioned that to me when I started going through it.
It really helped to talk to people though and see just how many people knew EXACTLY what I was feeling.
Yeah I have been to the grocery store and almost just left my full grocery cart and walked out.