Propane reaction medical problem. Please help.?

Hi. I have had a reaction to propane for almost 3 years now or anything with methane in it. I've went to see a doctor and he sent me for tests and they all came out fine, but whenever I'm around propane I become pale and barely able to breathe and as a after shock of all this I have some sort of spasm as to where my body is is just flailing around and i have barely any control. I ruled out that it was a seizure since I'm still aware of my surroundings and what is going on. If anyone can, please help. Thank you very much