You're not being paranoid. One of the changes in perception we go through is realising that lots of bad things might happen in life but pre-disastering everything and assuming the worst doesn't help a tad. You can't live like that and many of us didn't live like that before cancer. I used to get every imaginable ache and odd sensation annually before every test. So far this year (there's yet time!) I haven't. Which is, I suspect, because I finally realise I can't alter it if it's bad news and that I am also much better prepared for it. As @iserbrown says, ease up. This all takes time.