Being someone else

When I'm with my friends in always this happy girl that everyone thinks bothering is wrong with me.Well there wrong🤷🏼‍♀️I go home after hanging out with my friends and I'm just this depressed kid who shuts off her phone and doesn't wanna talk to anyone.So in my mind I feel like I'm two different people.And I don't wanna tell my parents this because I don't wanna disappoint them.My older sister used to have really bad depression and it put a lot on my parents.I just don't want them to go through it again.And my friends don't even know.So what should I do?