The cancer that will royally screw up your sixteenth year on this earth will not dominate your life, or at least not for too long. You are now twenty-one and capable of all you were before, plus more.The truth you learned while you were ill; that everyone cares, doesn’t hold true when the illness fades. However the people who pretended to care appear to create their own problems, or perhaps karma is teaching them a lesson they will never learn.
Breaking up with her was a mistake that could have been avoided perhaps, had diagnosis been sooner. She will be happy with her new boyfriend for years to come, and you wouldn’t begrudge her that would you? Of course you would, you’re sixteen.
Things always turn out alright. They always have. No-one is content with contentment, although it is the perfect state of being. Let happiness and sadness have their moments, but let contentment; stress free, nothing to worry about contentment reign supreme. That sounds cheesy as fuck, but I swear it is my own cheesy fucking statement, and may you live long, and be satisfied with your self and your life by it.