What is going on?

[burn]

I am a 33 year old female and have been in good health, with only having my gall bladder removed 5 years ago. After that, I felt great with no sign of a problem. Two months ago, I was diagnosed with Graves Disease and put on Tapazole. I also had to see a cardiologist because I was found to have extra heartbeats in the lower chambers of my heart. He put me on Toprol-XL, 50mg. daily. In addition to this, my stomach has really been acting up. I do not have any pain, but I constantly have acid reflux and sometimes I feel like I am going to pass out. I get incredibly lightheaded, my stomach gets tingly inside, and my arms and legs get very shaky. I have an incredible amount of belching, and this feeling can sometimes last an hour. My primary physcian put me on Nexium 40mg., and for a few days, it worked well. Now the symptoms are coming back. I could not get an appointment with a gaestroenterologist for three weeks, and Iam desperate for some help. My primary says it goes back to having Graves Disease, but I have a hard time believing that.Nothing  I've read about that condition indicates it affects your stomach.I guess my main concern is whether an ulcer of reflux can be bad enough to make you feel as if you are going to pass out. I appreciate your help. Kim