The people I was with were convinced the bible held all the answers to everything they ever needed. It never occured to them to look outside - in fact they descouraged me from doing so.
I did eventually talk to a counsellor, who gave me an immediate and simple explanation of what really happened.
At the time of the "fit", we were discussing baptism. I'd just been to a CofE baptism and witnessed sprinkling of water on the forehead. I decided to be baptised a believer myself but forgot I was doing to a baptist church - they practice full immersion there.
When my friends told me this, I became scared - as a child I nearly drowned in a swimming pool, so I'm afraid of water. I remember I tried to tell them this... but threw this unexpected and scary fit instead.
They thought it was demon possession - after all, it fitted their picture. They didn't bother to check that it might be something else... I did check and descovered I'd simply relived my drowning accident. My arms and legs thrashed around because I was "drowning" again, arising out of the conflict of wanting to be baptised but being scared of full immersion. I don't recall thrashing around in my accident - my counsellor helped me see I'd supressed that memory.