Trauma often makes people feel upset, overwhelmed and unsafe, even when there is nothing immediately unsafe in the present moment. 

We have a phrase called the "Window of Tolerance" which was first coined by Neuropsychiatrist Dr. Dan Siegel in his book "The Developing Mind". The Window of Tolerance is the range of emotional experiences that are comfortable to express, process, and integrate. 

When going outside of the "Window of Tolerance", it's easy to get "Hyperactivated" (Fight/Flight response- angry, anxious, panicked), or "Hypoactivated" (Freeze response - shut down, lethargic, foggy brained, depressed). 

Window of Tolerance Info: www.mindmypeelings.com/blog/window-of-tolerance

Guide with ideas for grounding, staying in the present moment: www.frasac.org.uk/resources/Window-of-Tolerance-Guide-.pdf