Do you ever feel like a passerby? An outcast? I sometimes feel like I am the sidekick, but I am never the hero

I have problems, issues, but they don't seem significant enough compared to my friends. I always solve their problems, I drove miles and miles, spent money and time for people who didn't do the same for me. No. Scratch that, wouldn't do the same for me. I have been broken, used, bruised and abused. I have been poisoned. Poisoned by their words, by their thoughts, by their actions. I LOVED THEM in caps, yet they left with a lower case goodbye. I cry myself to sleep every night thinking. What if it is me? What if it's indeed my fault? Maybe I didn't try hard enough, maybe I am not even a good friend. My skin scarred, scratched, torn and cut. Trying to channel the pain. Trying to see the world in colour on the days where everything is bathed in grey scale. I am trying to hold on. But I am crumbling. Falling apart.