chickadee, google 'menopause symptoms' and you'll be very surprised at how many recognised symptoms there are (35), and also what they are, some of which you would never associate with menopause at all but once you know about them, a light bulb comes on in your head and you think 'ah ha, so that's what it is!!!'.
the test you're referring to is called an fsh test (follicle-stimulating hormone) but is very unreliable for telling you whether or not you've started menopause or peri-menopause as it tests the level of hormones in your body at the time the blood is taken. during menopause hormones vary hour to hour, even minute to minute, so you could very easily have a false positive or false negative result and the doctor could say the test shows you're not in menopause when you actually are and vice versa.
unfortunately, unless you go down the hrt route, there really isn't much you can do except live through it and wait for it all to settle down, which it will eventually. even hrt isn't a 'cure' as you still have to go through a menopause when you stop taking it, it just delays the inevitable. better to tough it out and come out the otherside in my book. i was about 52 when the hot flushes started and they lasted about 3 years, still get an occasional warm feeling but nothing like it used to be. and you do get used to them.
our hormones all interact with each other so as you were warned it's all no doubt due to having your thyroid removed.
great being a woman isn't it?