I feel like my life hasn't started

F 17 here, I keep convincing myself that when i turn 20, I'll start to actually live. I dont even know what that means to be honest, I'm scared that when the time comes and I'm already 20 I still dont feel alive. I dont even know what being alive means, life right now has been pretty boring and everything just seems pointless. My life consists of being at school, doing homework, doing chores, doomscrolling.

I feel like school has been draining me even though I'm not putting that much effort and i kinda feel guilty for feeling that way since I know a lot of people who are putting a lot of efforts in their study. Whenever a teacher tries to teach my mind immediately questions "does it really matter?". Dont get me wrong I wanna be an achiever, but i dont know where to start and i dont have the motivation to do all that.

I've also pushed away my best friend because I felt like I was not needed and stuff. I dont even know how to approach her again since she seems to be doing fine without me (not that im expecting anything)but again it was my fault for ignoring her. It's not just my best friend but my other friends too, I pushed them away because they couldn't do things for me even though I've always done things for them. I'm just too tired to communicate with them or maybe i just hate confrontations, i honestly dont know.

I've also been doubting myself if I can even reach my dreams(becoming a doctor) because I've been failing my math subjects and I dont even want to fix that (I know i need to but i dont want to). Even if i did want to fix it, i dont know where to begin, i hate asking for help it makes me feel dumber than i already am. Even if i somehow find the motivation to learn math does it really matter because I've never seen a doctor solve a math problem to prescribe medications and shi. I dont want to learn unnecessary things. I feel like I'm being lazy and yeah i should get it together.

I dont know why I'm acting like this

Any advice?