What to do about this?

This morning, the guidance councilor pulled me out of homeroom, and said that a teacher smelled pot on me. I have never used any drugs or alcohol in my life, and I told her this. She seemed fine, but I asked who told her, and she wouldn't tell me. Doesn't the accused have a right to face the accuser? By law she must tell me, right? The school has not taken legal action against me. Can I get an order for her to formally tell me who, and what I have been accused of? What would you do in my situation.