I have so much stress?

I'm 14 and a freshman. im doing football and trying for linebacker there are alot of kids and i try my best but the coach doesn't notice i mean im pretty big and athletic. i feel so stressed out and i dont want to upset my mom for quiting even though she says i can i know she wants me to keep playing i just want to feel good about myself im very smart also i get wonderful grades in advanced cles and have a few close friends