how can I prevent myself from getting poison oak?

arghh!! I have poison oak…strangely, I even have it on my leg, although I was wearing pants while hiking. How did the poison oak oils get through my pants?? And what can I do in the future to prevent it? Also, at what point is it no longer spreadable? the bumps first showed up on tuesday, so almost a week ago…is it possible that I can keep spreading it if I scratch? I am trying not to scratch but have been scratching in my sleep and waking up from it…and I“m worried I may accidentally spread it to other parts of my body through scratching. I considered sleeping with gloves on but I just can’t fall asleep with gloves on.