Feelings of dread and excessive worrying are classic symptoms of anxiety disorders. The burning feelings you are experiencing can also be associated with anxiety. You are doing the right thing by getting everything checked to rule out other causes... however, in my experience, if someone thinks they have an anxiety disorder.. they probably do. Try not to worry about the test results too much. If it is something else than anxiety, you will be properly treated. If it turns out to be "nothing," you can get started with a treatment plan for your anxiety.
All the best..
I felt the exact same way for years and to this day I still do at times. I was diagnosed with a few anxiety disorders, and when receiving proper treatment I feel normal again.
Hope things get better for you.