I can't stand my life.
What about your life makes you feel this way?
I don't want to go to school anymore.
It's perfectly normal not to enjoy school, but you should still seek help if you truly feel you can't stand your life anymore. It's not good to feel that way and can lead to bad things. You should consider talking to a therapist so they can help you feel better about your life.
I don't see much sense in learning at school anymore.
Attending school and learning will help you have a better life later on. It will be worth it even if you don't see it now.