I NEED advice on my purpose in life.

Hello everyone, I am a 16 year old guy.

In recent years, I have taken a great interest in astronomy and space. Over the span of a year, I have learned about dozens of planets, possible ways the universe was created, evolution, nature and a lot of other scientific facts.

The more and more I learned about science and our known universe, the more and more I realized how insignificant our lives truly are. I mean, no one really thinks deeply about this type of stuff, and I think that everyone is so blinded by useless things that they lose track of our real purpose in life.

We're all just infinitely small things on a tiny speck of dust in an infinitely expanding thing called a universe. All we do is "work", do "homework" go to school, and all this other shit, but at the end of the day, if you just look up into the sky and see the stars, you remember that everything you do is truly irrelevant.

This realization has driven me to become very phlegmatic about everything in life. Most importantly, I barely even care about things like doing my math homework and concentrating on school seriously because I feel like everything is useless. I used to always get high 90s and excellent grades now I'm starting to drop to 80s.

Can someone please enter my train of thought and give me advice in my struggle to get stuff done?