@Ellie2311 - you GP said your last lot of bloods showed your thyroid to be fine. When were those bloods done?
Thyroid hormones are quite dynamic and even vary during our 24 hour cycle. When my own thyroid was going off-piste, my hormones stayed in-range for some time, just creeping ever closer to the hypothyroid range.
Personally, I always have my full results. This is much easier now I can access my medical records online. I have tracked all of my bloods, on a spreadsheet, since my T2 diagnosis in 2013, so I can recognise
my usual running ranges, and trends where things might be going "a bit off".
You mention you are taking sukarto/metformin - have you had your Vitamin B12 levels tested? For some people taking metformin, their B12 elevels can drop. low B12 can also be implcated with heair loss.
Personally, I'm not one for supplementing vitamins or minerals unless there is a proven deficiency, because it is possible to overdose on some vitamins. Additionally, I wouldn't ever go for a "Well Woman"/Multivitamin style supplement, as they usually have a little bit of everything, but not enough of anything to make a difference to a person with a deficiency.
I feel for you. Hair loss is horrible and it's a big thing for both men and women in different ways. I used to detest the days of clearing our the shower drain strainer, fishing out enough hair to knit a mini-me.
I do hope you find some answers soon.