murmurs can sometimes cause balance problems in blood gasses and contribute to anxiety. See if you can get your anxiety under control while the physicians are doing your work up. No sense in being anxious and sick too.
I am so sorry that you are suffering this way. Anxiety attacks can be very scary and make one feel like they are dying. If that is what you have, I'm sorry.
A mitral valve prolapse (heart murmur) is very common in women. For some of us it causes enough trouble to take meds. For others, it doesn't and many lead a long, healthy life with the murmur.
I stopped taking heart meds and started taking Hawthorn Berry and L Arginine for my murmur. Seems to work pretty well and when I saw my cardiologist, he said to keep it up and see him in a year!!
If you are drinking diet sodas, please stop. Aspartame is in all of them and is a rat poison. More and more people are getting sick from the diet sodas - some of them having symptoms of Multiple Sclerosis!
You don't say where you live - but if you live near where "fracking" or fracturing drilling is taking place, it can also make you sick.
Eating wheat products can also make you sick. Sorry. Many are finding that they are allergic to wheat.
I would be interested in knowing how you fare and what your doctor has to say.
Meanwhile, take a good multiple to be sure you aren't lacking an important vitamin or two.
Wishing you the best