Can you become epileptic later in life?
Definitely, yes.
I used to work in a pub where the landlord (who had no history of epilepsy) suddenly started having fits when he played the video gaming machines (which, regrettably, he was addicted to). He then started having fits at other times as well.
Is your problem related to epilepsy?
Probably not.
It sounds more akin to some form of phobia, where a feeling of tension/anxiety/nausea comes about, under certain specific circumstances, for no logical reason.
Chris