Why do we live?

I think every one has at some point in their life this thought of feeling pointless. I mean why are we doing all this?
Why do we study, clean the house, if everything is just temporary. I mean we are actually just ants in the universe, so tiny that even the word tiny is still too big. We are born; we go to school, eventually college, work, have a couple children, marry, maybe divorce, work a little more and die.
Are we doing all of this just for the weekend, for the 20 days vacation? So that we can do something fun then, something that makes our existence valuable?
I personally feel that if you have something you’re pretty good at, then it might be worth it, but what if you’re just average? Average everything, average grades, average talent, average entrepreneurship, just average. Isn’t it extremely depressing to think that you’ll leave the world and everyone will forget about your existence in a few decades?

I am young so that’s my excuse of thinking so deeply, but I think that everyone feels pointless sometimes. I just hope that everyone has a person who matters to them. That’s what I found out for myself, you don’t live just for yourself, you live for another person, a person who cares for you.
Maybe there’s even THE person out there somewhere. But that is a whole other story; I don’t want to get into.