I have to agree with the doctors, that this may not be anything to do with your thyroid. The symptoms that you described actually are symptoms of many different things-not just thyroid issues. They could be signs of perimenopause, but they could also be a signal that maybe your blood sugar drops a little low in between meals-especially if you are not eating as healthfully as you could be.
The best thing that you can do to check this-is to write down what you eat each day, and the time you ate it. On the next/adjoining page in your tablet, write down what time you have any episodes of nausea, dizziness, etc. as well. See if, after a few days, there is any pattern.
I, for one, am very very sensitive in this area. There is nothing wrong with my thyroid-andI am not perimenopausal. (obviously, look at my signature...
For instance-if I have a balanced breakfast that contains enough protein and GOOD carbs-then I am fine a couple of hours later. If I have refined carbs and not enough protein at a meal-in a couple of hours I get nausea, "shaky", hotflashes, etc. because my blood sugar has dropped a bit too low.
It would really help to know exactly what you are eating and at what time, and what time these instances are occurring.
Also-what kind of medications are you on, and what are they for? I also would like to remind you, that most prescription meds do not start working by the next day.
There are things that are meant to work "now" like Tylenol or Rolaids for heartburn...but most major medications like for high blood pressure, antidepressants, birth control pills, and so forth have to be in your system for a while before they start becoming effective.