I also have hypothyroidism and this happens to me... I'm not quite sure how closely the two are related, however.

Depends on age and if other conditions are involved.

Could be POTS

I'm the same way with my hypothyroidism, i drive people crazy with how cold i have to be kept, which is weird cuz it says a side effect of hypo is being too cold! don't know if this is normal or related to hypo tho. what i do is keep as many fans on as possible and take cold/warm showers, you get used to it over time and will feel amazing after! hope this helps

If I take showers that are too hot then I become incredibly nauseated and start seeing stars. I never attributed it to my hypothyroidism but it’s worth considering.