After sessions is always a bad time. Here, it's called therapy hangover. You are changing how you feel about memories (reprocessing) and that eats up brain power - sometimes a lot of it. As you take the pain away from one memory, it lets others process and the amnesia your mind created to seal off the trauma eases too, revealing more memories.
Understand your function will be reduced which means you don't have as far to go to get overwhelmed. You may not be able to do some things for a while. You may need to reduce your daily activities to minimal at times. It has been one of the most difficult things to deal with as at times you get unexpectedly overwhelmed by doing what seems to be simple things and that means a bad day tomorrow.
Four things that were key to me were:
-Monitor cognition. If it starts slipping then I am either in or about to be in trouble.
-Manage my stress cup
The ptsd cup explanation
-Realizing that all stress is stress. ALL STRESS IS STRESS whether physical, mental, real, or imagined. It's why self care is VERY important. Eating, rest, exercise, showering, brushing your teeth, all that is stressful to your body if neglected.
-Grounding and core belief counters. Practice until you are like me and the dental assistant asks what you are saying and you realize you are doing your grounding without thinking about it.