Hi
it feels terrible to be frowned upon, but kids are just kids, noisy and busy, especially toddlers. I also chose to stay home despite having a postgraduate degree. I took my children everywhere as even in my home country all the grandparents were still working when mine were young toddlers.
Hang in there, ignore the looks. Pick your times for shopping carefully, make sure the kids are not overtired or hungry. I know this is not always possible For seven years I had at least one child at home full time, no day-care etc. It can be a very enjoyable time, seeing the world through the eyes of a little person.
I find now that that they are all in school full time they are actually worse to take shopping because they do it less frequently. They whinge more and have more 'I wants'.
If you want a few hours to yourself you may be able to find a place to look after your children. I know there is a place here in Basel, based at a church where you can leave your children on a regular basis for a couple of hours.
Good luck