The unintended consequences of outlawing plastic bags: https://news.yahoo.com/cotton-tote-crisis-122835987.html
The last part of the article, pointing towards solutions, was useful stuff. Also worth noting that many thrift stores take cotton material and sell it to companies for rag fiber (used in paper-making, Green brands of house insulation, and other areas where fibers are usable). Also worth noting that plastic nanoparticles are now known to represent a massive threat to both ocean life (including our leading oxygen producers, the phytoplankton) and land-based ecosystems. Nanoparticles are presently being found in human tissue and our food supply. The article understates this a bit. The urgent need to reduce this outweighs some problems with cotton, and there is no reason we can't also use other less-problematic fibers (like hemp, as the article noted, or recycled fibers) for our tote bags. And yes, damned good call at the end there: not every purchase requires a bag.
But what's the other big culprit not mentioned? Mother Fucking Water Bottles. Just get a refillable steel bottle. Fill it with tap water. (the bottled water is just tap water from somewhere else. If you think you local water is bad, then take a jug to the supermarket, many which have those distilled water machines, and fill it there) Single-serving meals. Try brands like Amy's - the bowls are made from plant fibers, instead of polyethylene.