Never experienced having a locker. My high school didn't have them. Dunno if other Ateneo high schools have lockers, but mine didn't.
We resorted to stashing our stuff in broom boxes, under the platform at the front of the room, or inside the ceiling panels (only for students with rooms located in the top floor). Everything from guitars to food got stored in any of those places.
Also, it gets better, Light. There's hope for us thin folk. Working out coupled with truckloads of food worked wonders for me.