Anyone here with hyperthyroidism?

My THS showed low a few months back. I tested negative for Graves and heard no more about it from my doc, who moved shortly afterwards. My new doc wants to do another thyroid test. Especially in light of the symptoms I've been having; a constant mild shaking feeling which is more noticeable in the hands, heart palpitations and anxiety among other things. Looking back, for the last two years I've lost tolerance to caffeine and feel more jittery and anxious, so maybe this has been coming on for a long time, I don't know.

The strange thing is that I started noticing the shaking and heart palpitations six months ago, exactly when I also started having a burning pain in my chest and chronic diarrhea, which turned out to be GERD and gastritis (diagnosed with endoscopy). I was pretty sick for awhile, would get so weak and shaky that I had to lay down. My heart would pound so much I was afraid I was having a heart attack. At first the doc said it was all anxiety, but I eventually pushed for tests and they found GERD and gastritis and treated me for that. It's starting to calm down some but I still have the constant shaking. In fact the shaking has been getting worse and I still have heart palpitations. So I'm waiting for my new thyroid test results and meanwhile the doc is setting me up for a stress test. I've already had a normal EKG.

What's is driving me nuts wondering about is whether or not these conditions are related. I've never read anywhere that gastritis and/or GERD is a symptom of hyperthyroid but I have read that hyperthyroid could cause nausea and vomiting. I can't get completely rid of the gastritis, it seems, no matter what I do, and I've tried everything, so I wonder.

I also wonder if this is really hyperthyroid or if the shaking/palpitations are instead part of the GERD/gastritis. Is it possible to have a low THS level and not have a thyroid imbalance? I'd love to hear from anyone who may have had these kinds of symptoms or who knows something about thyroid tests.