I Hate Being Accused Of Something I Did Not Do

This was today like an hour ago.

I was taking a test and after I was done and a staff member saw me with my phone. My teacher and I sent somewhere to talk privately. She said someone saw me with my phone and it is considered cheating. And she asked me seriously if I cheated. I said no. It was true I didn't. I was honest. I dont think she believed me. She asked me five times if I cheated and said, "Are you telling the truth? You lied about being sick to skip summer school for one day so it's hard for me to believe you right now. The surveillance camerons are were on. I hope you're being honest. With your phone with you, it's considered cheating and a zero." I kept telling her I wasn't and I only checked my phone to see what time it was and looked at YouTube after I was done. I said, "I swear I was NOT cheating." She was like, "Okay....I'll give you a pass but next time you're getting a zero! You may go." I know I wasn't because if I did, I would have been a nervous wreck of they looked at the video.
I know I didn't cheat! If I did, I would have confessed. Damn it scared me for a minute.