Rumination.....

What is Rumination?  We can all do this about some thing or another.  It is thinking about something over and over, it is when the mind grabs on to something and keeps mulling it over and over.  This usually creates a non-ending cycle of lack of benefit or real purpose.  It is exhausting and stressful, a waste of time.  Ruminating thoughts are about problematic or upsetting things.  Your brain is in problem solving mode.  This is normal and can help to get us into problem solving mode and solve life's dilemmas.  However, if this system keeps going on and on, it can lead to problems.  This is one of the biggest predictors of anxiety and depression and OCD.  
So what is the answer?  When we keep ignoring the problems, the whole system will keep on getting louder.  So how about stepping back and using some introspection.  This is exploring something consciously.  Learning to self-distance, step back and view yourself and your problem objectively.  Research has found that when you do look at your problem from another perspective you become better at being calm and detached.  Try to visualize that you are an observer of yourself and your dilemma.  One  other technique is to use your name and not the pronoun "I".  

LENS neurofeedback can help you to balance out your brainwaves to become more centered when the stress sets in.