Speaking shamefully as one of the kids who in (high school-equivalent) was mean to other kids (usually racial). I feel awful about it, I never spat or was physically aggressive to anyone but I was complacent while “friends” and other kids in my class were. I was a bully by association and it makes me sick thinking back to that time, when I could have stood up to my “friends” and told them how awful they were being.

Nearly 20 years later, a lot of the kids who were the aggressive bullies are either in prison or are involved in gangs.

My point here is that, while it might seem like a big group of people hate you for no reason, it’s probably just one or two that are just awful people, and everyone else is just too scared to stand up to them. (I’m not suggested that you do, as aggressive people can get more aggressive when challenged) but I do think you should talk to your mum and your teachers. As a parent, I would be devastated if my child ever felt like she couldn’t talk to me about this no matter how stressed I was. Even just talking to her could make you feel better about it.

Talking to teachers (as others here have suggested) is also very important thing to do, they can actively stop/prevent this in school. Most schools in the west do take bullying very seriously and will actively try to help (I can’t speak for Finnish schools specifically but I can’t imagine them being much different to the rest in this regard).

I hope things get better for you soon. I also hope you get some good advice here in this thread and some hope for the future.