How can you tell if you have agoraphobia?

I have GAD and depression. Last winter I became increasing anxious. I used to take walks in my neighborhood, alone and it was nice. Then I started getting scared all the time, having intrusive thoughts flooding me with "what if" and it got to the point that I was not able to go to the grocery store alone. I have gotten a tiny bit better, but still have panic attacks at the grocery store and rely on my children to go with me. Its not fair to them that their mommy went crazy. After going anywhere anymore I am cranky, exhausted, or both. I have to spend a lot of time mentally preparing to go out to do almost anything social, and when I am there all I can think about is how I can get away and go home. I want my life back. What happened to me?