To be completely honest I feel a though these fears are perfectly normal. Why seek therapy for fearing something is wrong with my health.
Do you really think it's normal to assume you're dying every time something goes slightly wrong with your health? Do you really think that everyone who gets heartburn panics about having pancreatic cancer?
None of us react "normally" to things. Where a "normal" reaction would be "well, if it doesn't get better, I'll see a doctor," our reactions are to assume the worse. When the doctor tells someone without anxiety, "you're healthy," their reaction is, "oh good!" and they go on with our lives. People with anxiety? I don't need to tell you how that goes, because you're living it.
I know how frustrating and all-around crappy this business is. I do. I was "better" for a while before it started up again. And right now I'm in the middle of that "get all the testing done so I can feel secure enough to try and get back on the anti-anxiety horse again" stage, and fucking hell I did not miss this. This SUCKS, it really does.
Part of anxiety, at least for me, is feeling like I'm the rational one and everyone else is ignoring me. But once I get myself together, I realize that actually, everyone else was being perfectly reasonable, and I wasn't.