New Pilot Advice

I thought I had taken up this hobby with a lot of enthusiasm until
last weekend. Prior to last weekend I thought I was making steady
progress, taking off landing, developing some touch on the stick. When
I go the field I approach the flight with butterflies and some fear. I
was told by an instuctor this is good when you lose those butterflies
don't fly. Last weekend conditions were deceptive. Relatively windy on
the ground 10-15 knots but apparently much tougher high up (according
to the crusty old tow pilot). We took off with me at the contols and
everything was fine until about 300 feet and something hit that 2
seater from the side and we flew into the air above and to right of
the tow plane, the instructor took over and we proceeded up to about
1000 feet and I took over again until about 2000 feet where the tow
plane hit a sink and dropped like a stone (I've dealt with this before
but not to this extreme) I was not fast enough and the instuctor took
over again. By this time I was really frightened and my confidence was
destroyed. I did manage to take the plane over and get a clean release
at 3000.

We then proceeded to hit some incredible thermals and my instuctor
intorduced me to the fine art of climbing a thermal with other gliders
in it. The thermals were pretty rough and the vario was pegged at
times. He had me doing tight turns until I started getting air sick
(this had only happened on one previous flight). We continued to ride
the thermals until I told the instuctor we better go down. I tried to
hold on I know he wanted to stay up.

When we got down on the ground I did not want the instuctor to notice
but my knees were shaking. I do not scare easily, I have had a lot of
other hobbies where danger is involved. My question to you experienced
pilots is this fear normal? I was really frightened. If you knew me
I'd never admit it to you. Is this something you can get over? This
experience left me wondering is this hobby for me?

BTW when we got down they were cleaning out another 2 seater where a
student threw up (he was up for about 20mins), at least I stayed up
for 45 mins and did not throw up. At least I got some satisfaction.
Thanks