Hey.. welcome to PC... I think you should do what you can to get help for your depression.. that way you can be more helpful to your mom and sister....

You can't take care of them if you don't take care of you...
I know from experience that pretending can be exhausting.. it will take a toll on your body too...trying to force yourself to be something you aren't....

in your case trying to pretend you are happy and everything is wonderful in your world, when in reality you are lost in your own depression.. alone with it even...

I say get the help you need, so you can pull out of this dark place you find yourself in... you don't have to live this way hun.. you are so young... your whole life ahead of you...you deserve to feel happy.. feel the laughter...

Keep us posted... talk to us... we care.. Faith