I'm not happy anymore and i don't know how to fix it?

-i don't know why, but i'm just not happy anymore. i can act happy, but truthfully i haven't been happy in a while. i don't feel like myself anymore. i used to be cheery and bubbly and always laughing etc but now i just feel flat and sad and I DON'T KNOW WHY? i used to love seeing my friends but now i just feel tired when i do... having to constantly be 'myself' is exhausting. i recognize that i'm probably clinically depressed, i have a lot of the symptoms of it, but it confuses me because i don't have any reason to be upset. nothing really bad has happened to me in the last year, i'm pretty much overwhelmed with stress but i didn't think stress caused actual depression. I just want to go back to the old me, and i want to be happy, but i don't want to take anti-depressants. i just don't know what to do? please help.I'm so srry to hear this.... I'm kinda like it but I have my reasons.... It does seem you are depressed.... Idk how old you are but ou need to push yourself.... Being with other people will make you feel good.... Being around other happy people usually can influence someone to be happy around that person.... And did something happen when you were younger or a chain of events? If so that can be bothering you... You don't even have to be directly thinking about It, it could be in the back of your mind haunting you with you knowing.... Idk but keep trying to feel happier..... It's gonna be hard but it's worth it to get out of what your going through... But I guess it's easier said then done since me myself can't do this but I guess it's because I'm only 13