I went through a really rough, extended period of depression and anxiety a few years back. I became convinced that the tight-knit group of people I was friends with didn't actually like me. But I had just enough self awareness to remind myself that those kinds of thoughts were part of my condition, not an objective viewpoint.

Anyway, long story short, it turned out I was totally right to be paranoid and it was actually worse than I had thought. I've had plenty of dark periods in my life where I've had frequent suicidal thoughts. But that was the only time I genuinely wanted to go through with it. I almost threw myself into traffic on the way home that evening.