Why do I want to be at home so much? And why do I need breaks in between doing things/going places? I'm 15?

You probably just have a bit of an introvertive side, even if you don't normally seem that way. I'm that way and for a long time I just thought I was really weird because I started feeling uncomfortable if I spent too much time around other people. I enjoy it for a little while but then it starts making me tired. All it means is you need more time to yourself than some (or most) other people. And its totally normal.