Mean teacher HELP!!!?

so there's this teacher at my school and hes our librarian, he teaches us music theory ps im a grade 6 boy. so what happened was in music theory to me it makes no sense and the week before i brought my notebook home to study and i left it at home, then at the last time we had him my book was at home and also our library is really small so basically first he yelled at me and told me to find a computer when i said there was no more cause there wasn't!! then after about 30 minutes into the period he comes over to me and yells "DEVON WHAT HAVE YOU GOT DONE!!! me:nothing because there's no computers. so then he goes and kicks a student from another class and puts me on the computer with like 5 minutes left in the period! and i didn't understand what he wanted us to do so he sends over a girl in my class to help me. she shows me what to do so i do what she says, then the teacher yells from across the room "DEVON WHAT HAVE YOU GOT DONE me: im finished so he tells me to show him it in front of the class so i do. then he says its to good to be true and laughs at me in front of the whole class and then yells: I WILL GO THROUGH EVERYBODYS FILE TILL I FIND WHICH ONE YOU STOLE THIS FROM!!! which sent me into tears and then i yell back : I DIDN'T STEAL IT SHE HELPED ME! he continues laughing and then the bell rings and the period is over my friends try to comfort me but over this weekend i cant stop thinking about what happened and when i do i feel sick and tomorrow i have music theory and i dont know what to do PLEASE HELP ME!!!!