So, ah.. no grocery shopping?

So my doctor just told me I need to take it easy a little. I was playing with my toddlers (crawling around, chasing them, doing mom stuff) and got cramping. It got worse when I was sitting down so she checked me and said I'm not dilated or anything (thank goodness, I'm only 22 weeks) but that I need to take it easy and I ever get cramping again, to sit down immediately and drink a ton of water. Okay, that's fine.. But when I go grocery shopping, my cart gets pretty heavy. I start having minor cramping when I'm pushing the cart. But that's not exactly something I can just sit down while doing.. Any ideas?