Catastrophising involves imagining the worst is going to happen. If you are prone to do this often when it is not warranted by the evidence, it can cause you stress and anxiety and may also inhibit you from acting or alternatively cause you to act in ways which are counterproductive.
Here is a tip for managing your tendency to catastrophise:
Each time you find yourself catastrophising don't beat yourself up or chastise yourself or think you are never going to change this pattern. Instead, smile at yourself and make a mental note that you are catastrophising (again!). If you want, you can keep a checklist of how many times you catastrophise in a day (this can be simply a series of ticks, each tick representing one time when you caught yourself catastrophising).
Remember you are not fighting this tendency to catastrophise, you are smiling at it! We all have foibles and this is one of yours. Simply noting it and acknowledging it in an accepting way can help to bring you out of your mental turmoil back into the real world. That is why I say: if you are keeping a written checklist, write a tick each time you catastrophise, not a cross - since a cross would be like fighting or putting a black mark against each occasion whereas actually what you are trying to do is to accept that it happens and then move on.
Once you have observed your catastrophic thought(s) in this accepting way, try to focus on doing something practical to get on with your day!
For information about where you can get more tips for dealing with negative thought patterns, click on the link below:
CBT Techniques to Beat Negative Thinking