My FC told me how to prevent the mistake in the future, but I went on a trading rampage, and sold 4 head gears: Myth gear for SCH, WHM, MNK, and BRD. Luckily I had an i80 healer circlet and slapped that on and ran ST and won the healer head. I won an antique helm in roulette this morning and bought back my BRD head, then had enough sol tomes to buy a Weathered Gloam head.

I'm lucky enough to have recovered quickly enough, but I would like to see a buyback option for seals. Still, I fully own up to my own mistake and am thankful for the knowledge to prevent something like this again.