Hey there MD,
I think a lot of us have been in your same position...having a barrage of various symptoms that are very uncomfortable, multiple trips to the ER and/or the doctor, and results coming back negative for any medical issues. It's great that you've ruled out such issues, but that doesn't help you now because you're still dealing with anxiety/panic that can manifest in very uncomfortable physical symptoms.
What helped me was a combination of things. First off I read up on anxiety and what it can and can't do to your body. There is a great book called "Hope and Help for Your Nerves" by Dr. Claire Weekes... she talks about
anxiety, it's causes, and ways to cope. What I like is that the first part of the book talks about
your nervous system and how it can get overly sensitized so that your nerves on a very basic level get stimulated when they shouldn't, causing the adrenaline rush and subsequent panic and anxiety.
I then learned about
coping mechanisms by visiting other parts of this site and talking to my psychiatrist. This has been helpful when the panic and anxiety hits.
I've also accepted that I will probably need some level of medication assistance for a while, if not indefinitely. For me, I found that Lexapro helps a lot. I take a relatively small dose and want to keep it that way, but there's no doubt that is helped my overall anxiety be much more tolerable. Honestly, I think I've had low serotonin levels for most of my life, and the Lexapro has helped even things out from a neurochemical perspective.
Finally, I've just learned to accept that I have anxiety and that it's something that's more or less been there since I was a kid. This acceptance has helped because I don't get too hard on myself when the anxiety and panic hits. In fact, a lot of times it comes up and goes away within a few minutes and I hardly notice it.
Hang in there and post up often!