How do I tell my brother I'm on my period and he needs to buy me tampons?

My parents are on business trip and I am at my brothers house, I just started my period and I'm running out of tampons. I've just been staying in bed because I don't feel well and he keeps coming asking me what's wrong. How do I tell him I'm on my period and need to buy some tampons. This is so awkward and embarrassing.
How do I tell my brother I'm on my period and he needs to buy me tampons?
Post Opinion