Depression: First encounter (that i can remember)

Lots of things led into this. Its been an ongoing process for almost a year, going and going until i found myself in this place. In hindsight i should have seen it happening. Honestly, i don't know how i didn't. In october, my brother took cyanide pills and killed himself. He was on the verge of going to prison and despite a sentence of only 3 - 9 months, he was just too scared to go through with it. He also felt he was somehow "protesting injustice" but i guess i'll get to that weird logic later.
Anyway, this has been happening since before he passed. I can remember up until about 3 weeks before he died (the rest of my life before that seems to be one large blur, like it was not my life that i personally lived), and looking back i should have seen the beginning of a change. I don't remember that time well but i am aware it happened, and i am aware that i was not okay. The first night i remember the despair (the depression) it was a while after i had been informed my brother was talking about suicide. I was, obviously, very not okay about it. My boyfriend at the time (whose name i won't mention because you don't really need to know that, now do you?) was not very available that night, but that was the case for most of the nights during the school year. On average we could talk for about 2 hours a night with me waiting on average 45 minutes for a text. That night he did not talk to me at all. This was technically his fault, but he just really wanted a good future and needed to dedicate a large chunk of time to studying. It was my fault too, though. I chose to love an unavailable man, as an incredible needy woman, this was something i should have better examined. But, as it was, that was my situation. After a while the news of what my brother was talking about truly sunk in. I started imagining a life without my brother, and i became overwhelmed with emotions. I began sobbing almost instantly and frantically tried to get a hold of the boy. He wouldn't answer me, he was likely nowhere near his phone. In a panic i turned to my best friend (you're only getting my name out of this, ill have you know). Luckily he was able to help me recover slightly, but that night i broke up with the boy. This in and of itself was traumatic for me, so i became very unstable. After that my world becomes a blur until the news of my brother dying, but ever since i can always relate my depression to that incident. When the depression comes and swallows me, its the feeling of isolation and fear that comes back. It's one of the most crushing emotions i have ever known. Had my brother not stolen the thunder, and made dying an inability for me due to my love for my family, i would have killed myself by now simply to escape it.