londonboy,
As the other guys have said on the thread don't worry about it! I've been flying on and off for the last 8 years (although only seriously since new year when I started my PPL) and i've only recently just about built up a tolerance to air sickness. I used to feel ill if there was the slightest hint of turbulence
Strange thing was, I've done a couple of hours of aeros and I was fine! What I found worked for me was motion sickness tablets, Kwells are the brand I used. When I started my PPL I took the recommended max dose, then if I felt ok that flight I took a reduced dose next flight etc and i'm upto a point now where I only take the tablets if the weather is particularly bad.
Hope this helps!