Check your shampoo bottle label.
I don't know WHY I didn't figure this out sooner. It's the shampoo I use in the shower!
When I wash my hair, the shampoo runs down my whole body and (duh!) printed very clearly on the shampoo label is this warning: "FOR EXTRA VOLUME AND BODY"
---No wonder I have been gaining weight! Well! I have gotten rid of that shampoo and I am going to start using Dawn dish soap instead.
Their label reads, "DISSOLVES FAT THAT IS OTHERWISE DIFFICULT TO REMOVE". Problem solved.
