I feel exactly the same. When the weather is bad I can hardly be bothered playing games, playing keyboard, learning stuff, or even watching tv. Instead, I just sit here staring at my laptop.
It's occurred to me that much of this lack of motivation can come from the people around you. If they don't do much, then you don't either. I guess if I really wanted to I could achieve much more, but it would definitely help to have more motivated people around me.
I feel bad for saying it, but I think I need new friends. People that'll challenge me to learn new things etc.
If I hadn't started trials this summer I would've achieved f*ck all.
I'm actually looking forward to uni this year because it'll force me to achieve more.