This is a great place to share our similar problems! Family just thinks I'm nuts and that I "do it to myself", but it is honesty a mental problem for me! And I know what you mean about the age. I'm almost 46 and when younger I'd always console myself with "I'm too young for that!" and I could relax a bit. But now I say I'm NOT too young! And every single thing I get is the REAL thing (before if I'd get constipated it was just "normal", now at 45 it "colon cancer"; no matter what I get it goes away, I laugh at myself, then the next thing comes along (could be in 2 weeks, 2 days, or overlapping the current problem!) and I then think, "AH HA! All those other things I was being stupid about, but now THIS IS IT!" My latest problem was tingling arms, so then I "had" blocked arteries and blood clots - it doesn't end! Currently I'm in a smooth sailing mode, but I know it won't last!
I'm sorry, I know you asked how you could deal with any medical problems that come along, but I'm in the same boat as you and all I can do is "support" you.
As far as what Hry said, if I go to a doctor, I am happy for about a day, then my mind starts racing again, - "Oh no, I forgot to mention such and such! That would have been the clue!" or "Suppose he wasn't listening close enough and didn't HEAR the tell tale symptom?" and on and on the mind races...