Picture a 20-pound dumbell. The average person could lift it with small effort. The same goes for small pains. The average person can just repress it and move on. However, the same is not true for larger things, like depression and great loss in ones life. The small pains are the equivalent of lifting that dumbell once, simple and quick. The larger pains are more like lifting and holding it. Anyone could do it for a time, some for a very long time. But as the stress of that dumbell, that pain, increases; you have to focus more and more on not dropping that weight. Internalizing the pain of a great loss or depression is very much the same, at first, you can just ignore it. After a time, you start to brood and make your life more and more about that pain. You isolate yourself, and eventually, after you spurn their help for the hundreth time, those you care about will leave you with your grief.
Everyone has their breaking point. Even the strongest person can only hold that dumbell for so long. When you reach yours, you may find that there is no one to help, no one to help support that weight. And so it crushes you. It is for this reason that people should express their emotions. Not just happiness and excitement, but anger, fear, resentment, and all the other various nasties people have locked inside. You should bring them out, confront them, and defeat them one at a time. Do not be ashamed if you need help, we all do.
Or maybe, it's just me.