So, I made this bag out of odds and ends when my other gym bag was too much in pieces to go on.
It's basically a rectangle sewn to two circles (all pieces are two layers of fabric with quilt batting in between, although 1/4 of that rectangle is a strip of felted wool yarn), with a zipper. And most of it was hand sewn because I'm an idiot about construction. I didn't have a pattern... and I'm not sure I could reconstruct it now.
and the inside: