i think life is fun and i must be thankful and happy. i have a nice family, a dog, friends, a gf. my grades are average, i'm playing american football. i have nothing to complain about. yet i feel sad when nobody is with me. i wake up crying for no reason. i tried to talk to my gf but she doesn't understand coz i'm happy when she's with me. it appears like a lie when i say that i'm sad when im alone. talked to my mum too. she said i should quit sports if i'm too stressed for school. i'm not stressed. it's not the sports. i love american football. i would never quit it.
i think i don't understand the world and nobody understands me.

Human beings are social creatures we long for conversation and other people's presence. We feel like we need to belong. Maybe you are sad because you overthink things when you are self ruminating on yourself. Start feeding your soul.