Mental Harassment to a Student

Hello, I've been faced with biased attitudes, but now it is unbearable. First incident: it was during the presentation that a fellow male student spoke very rudely and i tried confronting peacefully, but a female teacher present there took his side. I brought the rude behaviour of said teacher in notice of my head of department, to no avail. Now one of male teacher taunts me about the complain. Another incident: They put up notice regarding my shortage of attendance in all subjects but on personally going to each teacher and enquiring about my attendance it came up that my attendance was not short, and suddenly a new list was put up. This was a day before the exams began. I feel these tactics are for demoralising & pressuring me. I feel targeted. Yet another incident: 4th presentation, i was appreciated my the teacher present there and he even went to say that I should be a microbiologist due to excellent explanation of my chosen topic and as I answered all the asked questions accurately; the results came out and I'm marked a 7 out of 10 which is the score of those who did NOT answer the questions or were not able to present properly. I'm working harder and harder, yet my grades are getting lower and lower due to this constant partiality. It's causing me a lot of mental strain and due to history of depression in my mother, I fear I'd succumb to the state of depression.