pee test at gynecologist?

it's my first time going on Monday (in 6 days) will they take a urine sample???? I took a plan b today and I don't want them finding out!!!! (I'm going because I've had bad period pains for such a long time and my mom wants them to do something about it like give medicine or something)  I'm 16!  I LITERALLY CAN NOT TELL THEM I TOOK PLAN B. because my mom will more than likely be in the room and if I say I don't feel comfy with her in the room MY MOM WILL GET SUSPICIOUS AND I WILL GET IN A LOT OF TROUBLE.