Susan,
Have you used any adhesives or barriers at all yet? If not you are on the right track. have had good luck with Skin Tac for many years now. I tried Mastisol for stronger adhesion in the summer months but I had a nasty allergy to it and had to pull the sensor, sounds similar to your experience. Others use Tegaderm as a barrier, hopefully some of them will post as well.
Hope you find something that works.