Can't Help Being Sad

Lately I've found myself being really sad all the time, I cried today for no reason. I don't know it's just tough when it feels like everyone around you is happy and stuff and you're not. I don't feel helpless or anything, just...alone kind of, even though I have great friends. Lots of people say that I should focus on the good stuff but it's kinda hard sometimes and I get really down on myself a lot. I guess I just needed to say this out loud or write it down and not keep it all bottle up all the time. Maybe part of it is just me feeling really stressed out from lots of different directions. Aaaagghhh lol, hopefully I don't sound too depressed.