Hormonal- Venting

So I live with my SO, his brother and wife. Went out and bought some poweraid yesterday cause I’ve been really wanting some the past few days. And when I brought it home i hid it in a room my SIL never goes in. Well she went and found it and drank 3 of the 8 bottles. I’m absolutely livid, and I know it’s just the hormones but I’m so PO at her.