You have a young daughter to take care, you must take care of yourself. I totally understand how you feel since you need the help so much but your husband never give a hand.
If you cannot take heavy things, can you buy a trolley for yourself to help you carrying things, just as the one we use for buying things in the market. I thing as least it will not make your waist painful again.
As you have to bring up your daughter, you must try every effort to protect your health.
Yeah !! buy a shopping stroller. I have very serious back pain too and I bought a shopping stroller. I'll put everything in the stroller so that I can use less strength. Also you can have something to hold on when you walk. I got my back pain from my BB too, one time I was lying on the floor and suddenly she jumped on my spine. After that, I have very serious back pain, sometimes I can't sleep and can't even walk because of that. You'll have to find ways to make your life easier.