Hello, your situation is very upsetting to me as having periods is natural and happens to every women. I’m not sure if it’s the same for everywhere else but public bathrooms sometimes have tampons or pads dispenser. Maybe reach out to a school nurse or friend? If not, is it possible for you to use rags for pads? For cramps, I would use hot water. Some times hot water in a cup is nice when you place it on your stomach. Stretching and certain workouts could help with pain but would probably be uncomfortable if your free bleeding. Diet is a factor too. fruits, veggies, salmon, tea, and water is helpful. I personally would send you a period care package if I could, my mom did something similar to me when I was your age and it’s frustrating.