....because it increases your baseline anxiety.
The big thinky part at the front of your brain that deals with complex emotions etc. doesn't work right with PTSD. Every thing comes in through the part that determines the level of fear to assign everything based on how much of a threat it is.
Two things that help. Give yourself space to think critically. Is the fear real, or is it a result of stress and anxiety? It takes time to sort it out. Second - managing that stress and anxiety and understanding the stress cup. When you understand that all stress is stress and that you need to manage stress always, you start getting better at not reacting out of fear and anxiety.
Nearly a decade ago (2006) I wrote The PTSD Cup Explanation, a simple view of how PTSD causes symptoms in day-to-day life. This article is an update to that original piece. Regardless of the type of trauma endured, the PTSD Cup does not change, deviate or apply differently to your circumstance...
www.myptsd.com