I used to be depressed, near suicidely in high school. I was that one kid that everyone in the school seemed to have decided to be the hated kid. I really don't know why, I did (and still kinda do) have a bit of a speech impediment that makes me difficult to understand at times, so maybe that had something to do with it.
And I'm not talking about for 4 years or something, from Grade 2 to Grade 11, I was bullied. A lot of it was subtle but still damaging. I can vividly remember once hearing a kid make a joke that made the whole class laugh, lightly laughing myself (not heard over anyone else or even that noticeable) only for everyone around me to stop laughing and look at me with what seemed like murderous intent, because I decided to enjoy a joke they all did. That happened quite a lot, where I would chuckle at a joke and kids would look at me, kids I didn't even know, as if my joy was somehow wrong.
I remember being punched in the face by a kid I had never seen before right before I got to class, he was pulled away by someone, and I just went into the classroom, sat down, and had a breakdown. The punch didn't really hurt me physically, I'm a big guy with a high pain tolerance, but the fact that someone I didn't know hated me so much as to hit me destroyed my psyche. It made me feel that, even when I do nothing, say nothing, and have just met a person, their default reaction is to treat me with rage. That I was just defaultly hated by everyone.
That fact that the teachers did nothing to help only made things worse. They would punish me too, always assume I was the bully because of my size and the amount of times incidents involving me happened, once laughed off my complaint about being grouped by some girls, and even wanted to give me and me alone detention when I came up to them panicking when a kid was threatening violence on me because he thought I was yelling at him.
If I were to list every thing that I can still remember happening to me, we'd be on page 2 before I was done. Point is, I felt universally hated, except for a few people, a few friends and my mother, my sister didn't help and my dad just wanted me to toughen up. It still made me feel like misery was just going to be my life and I can remember a few times looking at a knife, walking by a cliff, or by a passing car and thinking about just ending it.
If anyone has taken notice, this is why I really dislike people telling people thinking of suicide "toughen up" "death is not an escape" or calling people who did commit suicide "cowards" or "pussies" I've been there myself, so I understand the mentality behind it. I think the best comparison I've heard is that it's like a person trapped in a burning building standing by a window. It's not that death becomes appealing or that they are really sad at that one moment. It's that they are afraid of the approaching fire more than the fall. People commit suicide because they feel it won't get better, and any attempt to tell them it will get better is met with "they told me that four years ago and it got worst"
I managed to avoid suicide for two reasons. One, I managed to hold on to hope that once I graduated, and I never had to see those devils again, it would get better (it did) and that I decided to go the "Safety in indifference" route, where I just refused to feel anything and killed my emotions off completely. That worked for about a year until my mother died of cancer. That didn't break through my indifference, if that's where you think this is going, oh no. The one person closest to me and the one that always defended me when no one else would died and I felt nothing. I killed my emotions too well.
It was months later, during the last year of school, when all the kids seemed to have matured and grown a heart and stopped torturing me that I left safe enough to care again. Then I looked back, and realized that I didn't fucking cry when my mom died and to this day, the person I was at that moment terrifies me. That I could become that emotionally damaged due to what the kids around me did.
It's been years since then, and I have long made peace with that and left the sad little child behind and escaped depression, but it did leave me with quite a few scars I'm still working through, mostly how I hesitate to open up and trust people, and the fact that I'm am painfully quiet, and still don't talk to well, due to almost never talking as a kid due to what happened any time I did. It also left me with a deep understanding of what bullying, and the depression it causes, can do to a person, and know what is going through the head of a person ready to jump from a roof.
Tl:dr I was bullied by pretty much everyone at my school, my defense against suicidal thoughts was to bury myself in apathy, which led to me becoming a heartless person in general until I was freed from bullying, to only become terrified by that heartless person. I was left with a hesitation to open up, trust, and generally just talk to people in general that will probably never really leave me because the teachers never helped me.