(Vent in comments if wanted or needed.)

Tw: school (so real)

AITA?

So I do online school. To do it I gotta join zoom classes. Well during one of my study halls I heard a teacher say that for today and yesterday, we didn't have science. So, I did what every normal person would and didn't go to science class. Today I got a call from my mom of her screaming at me saying that I'm grounded because I missed science today and yesterday while there was a test. I told her that I was told BY A TEACHER, that there wasn't science. She's STILL saying I'm lying even though I said that I wasn't the only person who wasn't there. Me and her JUST had a conversation the other day about her not saying I'm lying RIGHT OF THE BAT. She doesn't get home untill later today, so I'm gonna talk to her about it. Am I overreacting?