I will start to write or force myself to think of something positive or begin to recite affirmations (sometimes silently if in a somewhat public place) and other times I breath deeply. Over time as I have let go of the control of the memories and more importantly knowing most of my triggers (I know I can never escape them 100% of the time)has been helpful. Remember what works for one, may not work for others. I have met survivors with the same issue who find putting on headphones and listening to music, others have breathing techniques, other do yoga. We all have our own little tricks, our new coping mechanisms.
In your family, are there stresses or things that cause emotional stress. These can be triggers, they were for me. Sometimes it is simple words, phrases, tone of the voice. You need to reflect back. One thing I was always able to remember before dissociating was what was happening around me then the blank and then the return. Think about the before and this may help you to identify your triggers.
It takes time and remember when you do dissociate you are trying to cope, survive and what happens may reflect a part of you that you have buried or denied. My T and doctors believed that is what happened to me.
I hope this helps and if I can help please let me know. You can PM or post here.
Best wishes
Kevin