So I can't take advil at school and I get severe cramps!?

I snuck 2 advil in my pocket once but I was so scared of getting caught. They won't let me take advil to the office to take during school. It wears off! (I'm at school from 8am-4pm) I'm going into 8th grade and last year I had gym last block and I literally couldn't move. My doctor told me to take 4 if needed. What do I do???? Plus we have random drug searches and one kid was sent to Juvy!