I'm a constant worrier, with control issues and a bit of compulsion thrown in there too. It's pretty bad.
I went to a councelor when I was in college and asked how to deal with anxiety problems. She basically told me to do this activity:
First: identify what you're worrying about and how it's making you feel.
Second: Decide if there's anything at all in your power that you can do to remedy this situation. If there is, do it. If not, move to step three.
Third: Is this something you can't control? If so, STOP WORRYING ABOUT IT. Because there is nothing you can do about it. You either need to prepare for what will happen because of it (to an extent) and save your energy/sanity.
For a while I thought I needed to go on anti-anxiety medication but my psychologist talked me out of that claiming that you can control your worrying by simply changing how you think (although that is not simple!!

).
If I start to worry I try to follow the activity she gave me and try to avert my thinking to something else.
I don't know if you're religious or what your religion is but most religions have passages/stories/etc that tell you to put your trust in the higher being and whatnot. Sometimes reading my Bible helps me.
This all being said, the activity doesn't always work and neither does thinking about something else. It takes practice and time.
At least we're all in this together..
