JustMySize seems to be one of the only (may be the only one) companies that sells 100% cotton Plus Sized Hi-cut panties.  Years ago the sizes were more standard than today.  I am a WalMart/Target 3X;  sometimes a 2X at Dillards/Macy; however, in the last 5 years everything has changed.  I am the same weight/shape (12lbs. less, actually) and have recently purchased pajamas that are 4X and snug;  the fit would have been 2X a few years ago.