I'm a nervous flyer who spends a lot of time as a commercial aircraft
passenger. My number one anxiety is that freefall feeling when the
plane drops, like you'd get on a rollercoster (I don't like those
either).

As a bet with myself, I bought a trial lesson at my local gliding club
in SE England. It started out with an aerotow to 2000 ft, which had a
bit of the dreaded turbulance (the instructor said "it's been a bit
bumpy all day"). But the rest of the flight was fun and when we landed
I'd have gone back up again if I could.

Does anyone know if it's possible for people to overcome the fear of
freefall through gliding? I'm keen to do some more flying, but I
wonder if my fear will be a barrier for me.

Another question is winch vs aerotow. My local club does both. I did
aerotow, but I saw someone else winch launch. The winch is much
cheaper, but it looked really scary as an observer: the glider must
have been at a 45 degree angle, and I wonder what the accelleration in
the cockpit would be. I'd like to try a winch launch, but I'm worried
that it may be too much for me. Can anyone give any insight to what
it feels like in the glider? There are plenty of youtube vids, but
they can't show what it feels like.