Hello, I Was In The Car With My Friends While

Hello, I was in the car with my friends while they were smoking tons of weed. I didn't want to because I don't do it anymore, but I didn't know what to do since I was with my friends. Even though I didn't smoke, I know I got second hand from being in the car. I am going on the pill for period problems and my doctor said she was going to take blood to test my thyroids to check to make sure giving me the pill was the best choice and I didn't need some other treatment. I guess my questions are, will it show up in the results? Also, is my doctor technically allowed to tell my parents if it did even thought they didn't ask? I'm extremely concerned with what will happen.