Of course I cannot say for certain, but this type of dissociation and psychic numbing can, indeed, happen during times of stress. It sounds like that moment was particularly intense.
I would recommend a full physical exam by your physician to check yourself out medically. This is important so that you don’t explore psychological treatment for something that may have a physical origin. Depending on the results you can either explore medical or psychological methods of relief.
In the meantime if you have not done any yoga, exercise or meditating I would encourage you to sample these. If there are helpful ways of coping with stress — these are the ones.
Wishing you patience and peace,