With you being in high school I don't have much in the way of suggestions. I am college and took about a yr and a half to now to considered one of the guys, but all the students I started with still know my history. I use the men's restroom in a nearly building on campus where there is little just of seeing someone I know. I would never use either restroom in the building where I have most of my classes. This does require some planning as it takes 15-20 min to make the complete trip.