The feeling you get after being betrayed by the one person you love more than anything else. You have put all your life in this person, and she left you in a terrible way, turning your entire life into an empty pointless void. Your chest constantly hurts, you are angry at the world, you force yourself to not think in fear of thinking about your lost love, and you want to section yourself off from society because you no longer have any tolerance for the mundane bullshit that makes up most of your time. You just want to be loved but you're less attractive because of your bleak, hostile personality. It is the worst feeling that you can experience, and the real tragedy is that, due to the greedy and deceiving human nature, it is quite common. Heartbreak can cause suicidal thoughts, and is a major cause of death. If you experience it, remember, it can be fixed. Do not give up hope.
I got dumped for my best friend a few months ago. I'm still feeling the heartbreak. I have lost a few friends, and my life is a lot less interesting.