iron suppliment
Have you had your labs drawn recently? If not, start there. We should have them done AT LEAST once a year. So if you haven't in awhile I'd request a full bariatric panel done... be sure iron, ferritin, B12 is on it (they aren't always.) Once you know your levels you'll be able to see whether it's an iron issue (multitude of other reasons for hair loss.)
If your levels are low... you'll perhaps need an infusion... newer infusion processes are about 30 minutes or so, a couple of times. So people no matter what iron they take, it doesn't stick... the double edged sword of having a malabsorptive procedure.
Hope it's easily resolved. Best to you.