Bullied at campus

I caught a girl cheating using her phone during exam. I also told on her to professor. She hides her phone in pencil case. But she said she was turning off  the alarm. However, why did she turn off the alarm while the phone is in her pencil case? And I don’t know why, all class member are attacking me and threatens me death or leave school.
My parents forbid me to leave. They also called me bullied me and they wished I never exist.

Hence, her boyfriend also attacking me. Despite I already apologize that girl, she still attacks me and demands me to fell on her knees.

No professor/teacher is on my side.

I have been cutting myself for many weeks.I have no one.

People judge me for everything