Well, it's been a few years since I seriously considered it, but there were a solid 6 months where I was suicidal.
A friend of mine had committed suicide about a year prior to my own suicidal thoughts, and my best friend since childhood attempted suicide a few months before that. I think that this played a role in my desire to end my life. During this period I was still completing my bachelor's degree, and had no idea what kind of job I would want afterwards. I was also high (on weeeed) from the time I woke up to the time I went to bed, and was becoming increasingly paranoid.
I was under the impression that the people I considered to be my friends didn't actually like me, and every time I hung out with them I felt like my presence was a burden on them. Whenever I would hear laughter my immediate thought was that they were laughing at me. This was with everyone, whether they were friends or just strangers walking by on the street. I felt like the only way to feel alright was to get high, but looking back I'm almost positive that it was making all of this worse.
Everyday it just felt like I was going through the motions that were expected of me. The only thing that kept me from actually killing myself was the thought of how my family would react. Basically, I just didn't want them to feel like they'd failed, so I kept on living.
The strangest and scariest part of all this, to me, is that I'm not really sure what changed other than I stopped smoking weed and started working out. I also spoke to a friend and one of my school's psychologists about what I'd been experiencing, and I was assured that much of what was happening was delusional. That seemed to make something "click" in my head, and I started to feel happier and gained more self-confidence.