Why this? Because when I was 16 my life was irrecoverably changed. I went from healthy to disabled overnight. I've spent years of my life ripping myself to pieces for not doing more here. But in the end I just couldn't, and it wasn't my fault. It's not your fault either. We do our best.
Comparing yourself and your situation to others is utterly invalid due to the fact that nobody starts at the same level, nobody faces the exact same trials and tribulations. You do the best YOU can and take pride in YOUR victories, no matter how small you think they are.