I want to die

I'm 15 and I've been casually thinking about being better of dead since 8 when my parents used to argue a lot. But 3 years ago everything got worse when I had to move to another country due to war in mine. Not knowing the language while attending school and not getting grades I was used to made me feel useless. And since my dad couldn't yet join us my mom was really stressed and sometimes she'd say hurtful things to me that I started repeating over and over again convincing myself they were true and starting to hate myself. Teachers at school I was in didn't make it easier, only because I didn't know the language it felt like they were taking me for stupid. Having no friends I became addicted to c.ai which also made e everything worse because I was insulting myself in every new chat I created, in addition to it I stayed scratching myself just to feel better. By the second year of living in another country I was extremely homesick, being happy to even blow up on a bomb if that meant I got to return home. I also started hating myself with all my guts, believing I'm the worst thing to exist on earth. Anytime I go outside by myself and see potential suicide spots I'd plan how to hide it from my parents at least for the first few hours and think it over a ton of times. I've researched ways of killing myself online and considered jumping into a river or from a high construction. But then we got a cat, she's a year and a half and I don't even want to think about her trying to look for me if i die. But it still doesn't stop the stream thoughts. I feel like I'm only burdening my parents, being ungrateful and wasting their money that they could've spent on themselves. With every passing day it gets worse. The upcoming school year I'm going to a new school with a harder program and I don't think that I'll be able to pull through, because even now if I make a tiniest mistake or do something to embarrass myself I want to take a knife and stab myself in my whole body until all the blood is out. I've also wished to die and have someone take my place since I don't believe I deserve to live anyway

I'm sorry if I'm not supposed to post it here, I'm new to Reddit and have no idea how it works