Can I lose my health insurance?

Let me start off by saying that I do not do drugs. Addiction runs in my family and its not appealing to me AT ALL. So my situation is this: I was at my sisters last weekend and we were all sitting in the car listening to music when they lit up a blunt. I told my sis that I couldn't be in the car bcuz I didn't want pot in my system, she assured me it would be fine. I was an idiot for listening because they hotboxed it and I got a contact high. I immediately got out once I figured it out. I am covered on my husbands insurance, and I think I have bv (happens a lot). I am going to go to the e.r. to get it figured out and then the gynecologist next week. My concern is that they will have me pee in a cup (as usual) and drug test me (they have before) and my insurance company will find out. Can I lose my coverage? Like I said I never do any drugs and I made a stupid decision staying in that car.