Telling THIS woman not to worry is like telling a waterfall to just "plug it up". It seems that, along with the natural nurturing instincts we have as women, we also have this innate ability to worry about things that might never ever happen (and personally I'd gladly trade that for map-reading skills. Or more upper-body strength. But I digress.)
Excessive worry does more than just stress you out. It can reduce your body's natural resistances to simple illnesses. It can make you procrastinate. It can make you form facial wrinkles before your time. I ran across this article recently that gives some really good tips for focusing on the things you are worried about, and rationalizing through what to do with the worry. I hope it helps you as it did me.