Anxiety and worrying is caused by one simple, solvable mental state. It is caused by the desire to avoid a particular situation, whether inevitable or otherwise.
The solution is pretty simple: whether or not what you worry about is likely to happen, one simply HAS to totally accept the possibility of that particular situation occurring. Once you totally accept that what you are worried about might happen, it won't trouble you anymore and you can go on with the rest of your life peacefully.
Our problem is that we keep trying to somehow avoid the mess by doing a number of things that wouldn't change the probability in either case. Worrying is one of these things. If you accept the likelihood, you will end up freeing your mind to realistically evaluate and tackle the situation.
Trust me.
For a good starter on the concept of acceptance, see the relevant portions of Ekhart Tolle's "The Power of Now".