I agree with Marda.
Stress leads to anxiety.
Stress isn't good for you. It makes it hard for your body to fight things off.
I take anxiety medication because after having shingles, if I get the slightest twinge in my back, I'm scared to death that I'll have another outbreak. As a single mom, I'm under a lot of stress that I can't really control, such as the stress related to my job. I've just had to learn to manage it. Worrying excessively is very stressful and leads to anxiety.
Talk to your primary care physician about the possibility of combo depression/anxiety.
In the meantime, try to think of it this way....everything that's been ruled out is one less thing to worry about. I know as well as anyone else that it's very frustrating to go to the doctor and not readily receive a diagnosis so we can just handle it. But, as things get checked off, see those things as a good sign.
Give yourself time each day to really, really relax. Don't make excuses for not doing it. Take a nice bubble bath with epsom salts or just lay down in a quiet room with your eyes closed and envision positivity. Envision all the things you have to be thankful for. Stay in a hot shower until the water runs out.
Exercise is also great if you aren't too dizzy. Take a walk BEFORE dinner. It gets your metabolism going and it releases endorphines. Gentle yoga and some stretching may help.
Talk to your doctor. Ask him to sum up all the results for you and mention the possibility of anxiety/depression.
Hang in there and best wishes.