I don't believe I suffer from anxiety. (Is this why I can't get better?)

Yes, a lot of people on this board have health anxiety and often have panic attacks from it. It is fairly common. Check out of some the posts on this board and realize you are not alone.

I have been thru this twice and did finally get past it both times. I had the same problem, I truly believed that I was not well.

What helped me the most was going and getting checked out by several doctors and ensuring in my mind that I was indeed fine. It was a long process, but I finally let go, and the anxiety and panic went away.

I wish all the best for you.

Doctors can be fun..NOT. I had mine and my Mum (who I see rarely) tell me they thought I was depressed (ive been depressed before) but I knew it was anxiety...thats what I kept telling them! Eventually they got it (which decreased my anxiety..lol).
I had the same heart pounding racing as you (I even bought a stethoscope from ebay to listen for myself after nothing came on the heart monitor). I had no related health problems..but I did investigate..as you rightly should.
Perhaps you could try a few of the things I tried to decrease the heart racing...?...limiting coffee and sugar (not totally of course we need coffee and chocolate)...a little quiet time everyday just listening to your breathing. You can try and count how many breathes you take in a minute and work towards slowing it down everytime (harder than it sounds..if you like a challenge? you could try with your heart to).
Perhaps you know of other calming techniques..? In a course I did they suggested a time in the day for worrying...worry it out...then let it go for the day...you can come back to it the next day during worry time again.
you can also write down your problem/s and try and come up with several solutions then work out steps to get the solution you want. This may give you a path to walk while you are figuring out what it is thats going on with your body. i found it gave me purpose and power to take action...but i couldnt do it all at once..it did take time.
Sounds like you could do with a good sleep too...maybe you could crash at a mates for a night to get away from any drama perhaps you may relax and sleep well for the night. I found that it was very easy for me to get into patterns of behaviour because of circumstances so sometimes you need to be creative to break them.
I hope you figure it out and feel well soon.

In the beginning, I always knew I felt anxious and would get butterflies and shaky hands even back in school if I had to talk in front of the class.  My anxiety/panic finally blew wide open in 1982 and I fought the idea that I had anxiety and depression. 

I learned that accepting my dx and working through my anxiety is a huge part in learning to live with anxiety.  The hardest part is sharing with friends and family when you feel anxious as they don't know why you would feel anxious and tell you to " just relax", your going to be fine. That comment alone is a guarantee that my anxiety is going to spike as now I have to live up to "others" expectations and "just relax???"

Keep talking with us and know that we are here to support you.

Kindly,

Kitt