I recommend a few tools and coping skills I learned in CBT:

Prepare a list of 'Advantages to thinking this worry' against 'Advantages NOT to thinking the worry'

Then, my favourite work, is to deconstruct your catastrophic thinking. Make a three column list: Worst Case Scenario/Best Case Scenario/Likely Case Scenario. Chances are, that last list is going to be the longest. Now, take a look at those things that are on the worst case list and consider if they really are or are not realistic. If you are still of the mind they might happen then this is your opportunity to make a plan for the event they do.