Serve health anxiety

I've just been diagnosed with health anxiety and I have horrible thoughts all the time I'm always stressed and worrying about somthing to do with my health I'm only 17 since I've been diagnosed (2months ago) I've had stomach fullness feeling and headaches dizzyness my gp has done blood tests to rule out certain things and also done a stool test for h polyi bacteria and everything came back clear just worried that my health anxiety is caused by some pyhiscal illness they also put me on SSRI zoflot 50mg and I'm waiting for CBT