Low level, I feel the same as you. It seems silly really.
Maybe it's made worst because one minute we are flying at 200 feet maybe, and then next minute at 2500 feet. The sudden change in height feels like one is in outer space, since you are twelve times higher.
I do feel as though I have got better though with time, although I'm still not totally over it yet. My wife has studied Psychology and she says one needs to de-sensitive oneself from the fear.
If for example you feel totally ok up to say 1500ft. Try flying at that height for a while. Then do some gentle manoeuvres, the same manouevres you would be comfortable with at a lower level eg. steep turns, flying at a slower speed and yawing the gyro around. This might psychologically tell your brain that just because the gyro is higher, you won't fall out, and that it is ok. Then try flying slightly higher, say 500 feet higher, and then trying the same thing, only when you feel comfortable with the height. The aim is to "practise" flying as high as possible, whilst still feeling comfortable.
Doing this might help so that one day, when you are at a very high altitude, and you do encounter turbulence, you won't get a tight stomach, and your brain will tell you that you will be ok, without the fear factor.
Try this, see if it helps. In theory it should. When I was up there at 6500', I did a steep turn, and I think it might have helped a bit. The trick is to "practise" some high flying now and again to keep oneself de-sensitised.
There is also that self-hypnosis that you can try, when falling asleep at night, that will train your subconscious to also believe that you don't have to fear heights.
Good luck. Hope it helps.
