Happy?

I thought everything went pretty well for me until...
It's always like this. When you're happy for a moment, something have to crush you down. You can't always be happy. It's impossible to be happy. It's hard to be happy. But all I want is to be happy. I envy and wonder how people can be so optimistic and positive about every single thing. Even though I laugh very easily, but I cry very easily too. I HATE IT. I HATE TO CRY. But I can't control my tears. Why am I so emotional? Whenever I'm down, I feel like... I have no one to turn to. Nobody. I feel so lonely. Is it because I'm the only child? Is it because I don't have a lot of friends? Or is it because I feel that no one will ever understand me? Whatever it is, I hope that sad times can pass by quickly, and happy times lasts longer. Please.

"I choose to be happy, so I didn't have to explain myself to people who'll never understand. Smiling has always been easier than explaining why I'm sad."