Benonianto,
Have a look here -
Earning My Wings: a video blog about learning to fly
I was hopeless at working the radio when I first started (some may say that several thousand hours later, I'm not much better
). What I did was to write down everything that would happen during the flight in relation to the radio.
So... what I would hear on the ATIS, leaving blanks for the differences, (ATIS information ?, time ?, wind ???/??, visibility ?, cloud ?, temperature ?, dewpoint ?,).
Then what I would say to ATC, again leaving blanks for the differences (Ground, this is N????, at ?, with information ?, requesting taxi/clearance/?), exactly what their response would be, again leaving blanks for the differences. Eventually, I found myself using my cheat sheet less & less, until I stopped getting the "Oh sh*t" blank moment as soon as I pressed the PTT.
Doesn't solve the sickness problem, but maybe if you work on each aspect of the flight, and reduce points that are contributing to your nerves, one by one, the sick feeling will gradually disappear as well.