Annoyed

I have to buy Boost drinks every 5-6 days for myself and my sister (25 this Saturday) knows I need them. I go into the fridge this morning to get my last drink and guess what? It's not there because my sister decided to take it. I'm perfectly fine with sharing something that I bought, but if you're going to take the last one at least tell me like damn. If I'm not there to be told you're taking it, just don't take it because I hate going to go get something expecting that it's there, and then it's not. Millionth time she's done this and I'm getting real tired of it. If you're going to drink my nutritional drinks that I need for my health than you're gonna help pay for them cause they're expensive