Hi there
I think a lot of it is also to do with generally getting older as there is the likelihood of more things going wrong (like a car!). I think also we are more aware of our health & bodies etc these days and meno heightens this for some reason, it's almost like you are on standby for something to go wrong. Plus of course until I started on this site I had no idea how much oestrogen plays a part in so many body functions so declining levels are going have an impact all over. 
Reading a certain daily newspaper doesn't help either as they seem to be obsessed with health stories of what are probably very unusual cases but puts the shivers up you. Plus we hear about people we know having health issues so if you get a symptom then eeek is that going to happen to me! Although is it better to be aware and then go to the docs just in case, who know's what is right. Although I agree it all gets pretty tiring!
I recently read an article about how some people have "binge thinking", chronic over thinking, so your boss tells you off and by lunchtime you've lost your job, house and living in a cardboard box, same applies to health, you get a twinge and it's worse case scenario. This is certainly me, I've always erred on the pessimistic side but now is much worse since the hormones disappeared! I did mention this to my doc but she said it was a personality and or ageing thing, something you would have just brushed off when you were younger now is a major panic. 
Certainly this site helps so much, when I was having the weird head thing I thought phew, the other ladies have reported this so must just be a hormone thing. It certainly helps to share all this info!