Discovery Flight today...unexpected results

Hi all. I'm a 39 year old guy who has loved flying and dreamt of
being a pilot for a long time. This year I finally realized that I
had more than enough money to start and figured I owed it to myself to
book a discovery flight with every intention of seeing it through to
my private pilot's license. I've also spent a ton of time through the
years on various PC based flightsims, and on them I've flown a variety
of aircraft and understand the instruments and navigation.

I've flown many times, and a good friend of mine has a Piper Saratoga
that I've flown in several times and even took the wheel for short
periods of time during cruise. I've never experienced anything other
than joy for it.

My flight instructer quickly introduced himself to me and did a very
short inspection of the plane. He then told me that I would basically
be piloting the plane through take off, the cruise through the
practice area, and landing. At that point I essentially broke out
into a cold sweat. I was able to get the plane taxied and off the
ground, and never at any point did I make any real mistakes or have
any bad maneuvers...but I was clear EXTREMELY nervous...to the point
of sweating. My instructor picked up on the fact that I was nervous,
and kind of just kept repeating "It's really not good to be too
nervous...that can be a problem" and other words to that effect. Once
we levelled off at 2500 feet he had me do some slow turns...still
nervous...death grip going on big time. He wants me to turn the plane
all the way around and go the opposite direction back towards the
airport. I'm turning the plane, but I don't know...I was just so
nervous of turning too hard. It was also a windy, choppy day so many
times the actual feeling of the wind throwing the plane around just
made me scared to maneuver it.

At that point the instructor decided I'd had enough and took back over
the controls. Immediately...nerves gone. The chop...didn't care a
bit. Total relaxation through a landing which even my instructor
admitted was a difficult one for him. I felt pretty dumb for being so
nervous.

At this point I don't know what to do. I've got the money, and deep
down for years I've wanted to do this. But I know that I can't
continue to be that nervous and continue my lessons. It simply can't
be good for my ability to make decisions in the air and I know that
scarier things like stalling and landing are coming up.

On the other hand...I also don't know about the instructor. He wasn't
overly helpful in combatting my nerves, and I have a feeling that the
right words of encouragment, or for that matter the occasional
instruction or "you're doing fine" maybe would have helped. In a lot
of ways I felt like he kind of just threw me out there before I was
ready mentally...I don't know.

Any feedback or experiences anyone can share? At this point I'm
really torn about trying again, while on the other hand still not
necessarily ready to back down from the challenge. Does this get
better? Or worse?