Hi Nate and welcome!
Well I can tell you that you are not alone...in your anxiety, symptoms or health worries!
We have so many members here who describe similar issues, and I can relate to many points in your post as well.
What is anything have you tried for relief from the anxiety so far?
I ask, because there are many things that can be done at home on your own for relief.
It sounds like you are working with your doctor to rule out anything physical in nature and that is good...follow through with that for sure.
However, I am going to post some links for self-help that you can be getting under way with in the meantime.:)
Health Anxiety - A Self Help Guide:
http://www.nhs.uk/conditions/hypochondria/pages/introduction.aspx
Helping health Anxiety
http://www.cci.health.wa.gov.au/resources/infopax.cfm?Info_id=53
Self Help sites with breathing/relaxation exercises instructions
Panic attack relief exercises:
http://www.healthcentral.com/anxiety/c/73076/34334/breathing-lessons/ (improper breathing/hyperventilation which we often do unknowingly when stressed can cause dizziness...learn and practice breathing techniques!)
http://www.healthyplace.com/
http://www.stress-relief-exercises.com/ (check out the progressive muscle relaxation exercise here for relief of neck tension, which can exacerbate the off balanced feelings)
http://www.ehow.com/video_4405003_breathing-exercises-panic-attacks.html
http://www.psybersquare.com/anxiety/panic_relax_I
Check out these links, and see if anything looks helpful to you. Keep posting with us as well. We understand, care and are here to listen anytime. Support is key!
Talk to you soon,
Scaredy Cat