Snips and Snails and Puppy Dog Tales

It's almost certainly your hair that's doing this (as a fellow long hair wearer, I've caused this to various extents myself). If you've got the kind of drain plug that you pull up and down at the drain itself (as opposed to the kind that you hit a lever on the side of the tub below the faucet), see if you can unscrew it. If you can, there's probably a crossbar below the drain plug that's covered in your hair. We actually need to clean ours out again due to this right now, ankle deep water when showering ftw.