Holiday activities/shopping anxiety

I was supposed to go shopping with my mother to put the kid's Christmas stuff on layaway the last 2 Tuesdays.   I keep putting it off.  This is the last week that she will go with me, and so I have to go this time- and I'm nervous.  I just don't want to go out to the store.  I never had a problem going out before, but now that I'm not working I go out less and less.  I prefer it when I simply don't have to leave the house at all.  I go more and more time between going grocery shopping, and it is showing.  I go grocery shopping on weekday mornings when no one else is out so that the store will be empty, but lately the kids have needed me to bring them out after school and it feels like the crowd is following me around the store and I can't find room to think.

So, with the holidays coming I am worried about parties and stores and traffic and I'm not sure I can handle it.

Is it possible to have social anxiety increase because you don't have to be social anymore??

I used to work in department stores and enjoyed the holiday rush, for goodness sake!  I would work the crowd and have a wonderful time! Now a crowded street to get to the store is enough to keep me in the house. 

I just don't want to go outside.  Can I seriously change this much in just a couple of years?  If I just try harder will I be more comfortable, or will it just freak me out worse?  Could it be that I am so used to being in my livingroom where my family of 5 seems crowded, that when I get to anything bigger it seems out of control?  Or could it be that I am simply getting worse and in a few more years I'll never go anywhere?  Or maybe it is just the holidays and in 3 months it will all be better?  Between now and then I have 4 church functions and 5 extended family gatherings that I have to suffer through. (I had to remind myself to breathe just then )

Yes, that could happen in a few years, or few months.
You have acknowledged how much it helped you or you enjoyed being at work, mainly because of the "light" nature of the exchange. Family/church people require more energy, and last longer. At home, everybody sort of knows their place and you expect them to be the way they are. Its comfortable. The holidays are laden with social interaction.
Get out and don't wait for this to go away. Making it the easiest, as when there are no crowds is a healthy solution when you can arrange it. Shopping, "early" church service.
If you get the toy layaway done you will feel the load lighten a bit. And you have your mom along so you don't go overboard. Pretty good arrangement.
The other stuff, if you can't eliminate some of it, pre-med for anxiety helps. Call the doc. You don't have to talk alot, just do what your therpist does, ha ha, answer a question with a question, people love to expound on their own stuff if given a little encouragement. Don't expect yourself to be the life of the party or bubbling all over if its not you. And even if it was, its OK to simmer down.
And regarding women's groups and the like, sometimes it helps to see how dis-combobbled other women are too. But then thats enough, and if it doesn't feel good, why are you forcing yourself to go? Decide what things are optional for the time.
Going out doesn't have to be with/around people. Pulling over and taking a walk at the park is nice, the mall early enjoying the decorations, music, smells, water features, is a nice outing. Going to the movies is nice, early matinee is cheaper, its practically deserted, and you can get a kids deal with popcorn and a small drink.
If you can get yourself out anywhere, that is better than becoming more and more isolated.