I think about what led to the situation, make choices about what is really important to me, focus on what is and work with myself until I adapt to it, or if it's not important I have to decide if I'm going to dismiss it or build some rules around it so that next time it happens I am better equipped to create a positive outcome.

As far as how does my personality/routine change during that time I just listen to my mood and how it resonates with everyday choices and then act based on that. This is not necessarily the greatest thing in the world for keeping mental stability over the long run but it works in the now.