FSH tests are not conclusive - as Dr Currie says on here re FSH:
A normal level does not exclude early menopausal transition and a raised level does not exclude continuing ovarian function. One raised level should therefore not be relied upon as a reason to stop using contraception since egg release can still occur late in the menopausal transition. http://www.menopausematters.co.uk/diagnose.phpAlso FSH can go into the post-menopausal range before you are post-menopausal.
The interaction between thyroid hormones and reproductive hormones I gather can also play havoc with your system and there is some symptom overlap so this could also be part of the explanation why you experienced the sweats so suddenly.
You didn't say how old you are either?
Do not fret at this point - you would be likely to have other symptoms if you had cancer - but it's natural to feel worried when you first experience these sweats.
Hurdity x