Keyreaper gave good advice, but some other things I'd recommend doing; do some stretches about 30 minutes before you go to bed, so you feel how sore your muscles were, and how they feel now. If you do enough activity as you imply, then you should feel tired by the end of the day, unless you're superman. Also, I'd suggest you masturbate or somehow release sexual tension before sleeping. I find that I usually can't sleep unless I do this, but once I do, I sleep like a baby. You shouldn't dwell on 'what if' situations, because they never go anywhere. You could sit there for eternity and ponder about them.
As for the self-esteem issues, just think about things that make you feel good. This is actually very simple in nature. For example, stand in front of a mirror and flex. Perhaps it makes you look like a douchebag, but at least you'll feel good about yourself. Think of how you fought that popular guy last year. Relieve every moment of the fight, highlighting the good points. Recall the expressions on all the other students' faces as they watched. Recall how good it made you feel to get all that pent up anger out of you. Think of the kids at your school who don't really have friends / are outcasts; at least you have people whom you are close to. It doesn't matter that you sit at the 'nerd' table. I mean, the table you sit at doesn't determine your personality; don't think for a second that it does. I'm sure the guy you fought last year sits at the jock/prep table, but that doesn't make him better than you, does it? I mean, you pwnd him, or so you say. Don't sit there and think, "Sigh he gets all the girls" or "I bet he's so rich" because that's all superficial. It all is. High school is one huge popularity contest. Don't let it get to you.
I'm also addicted to the Internet, but what does it matter? I mean, as long as you work out or get some form of physical activity and social interaction, then it doesn't matter. There's a lot to be learnt from the Internet; don't look at it as a bad thing. Would you rather be out destroying your liver by getting piss ass drunk and fuc|king random girls you'd never even met before?
Good luck
As for the self-esteem issues, just think about things that make you feel good. This is actually very simple in nature. For example, stand in front of a mirror and flex. Perhaps it makes you look like a douchebag, but at least you'll feel good about yourself. Think of how you fought that popular guy last year. Relieve every moment of the fight, highlighting the good points. Recall the expressions on all the other students' faces as they watched. Recall how good it made you feel to get all that pent up anger out of you. Think of the kids at your school who don't really have friends / are outcasts; at least you have people whom you are close to. It doesn't matter that you sit at the 'nerd' table. I mean, the table you sit at doesn't determine your personality; don't think for a second that it does. I'm sure the guy you fought last year sits at the jock/prep table, but that doesn't make him better than you, does it? I mean, you pwnd him, or so you say. Don't sit there and think, "Sigh he gets all the girls" or "I bet he's so rich" because that's all superficial. It all is. High school is one huge popularity contest. Don't let it get to you.
I'm also addicted to the Internet, but what does it matter? I mean, as long as you work out or get some form of physical activity and social interaction, then it doesn't matter. There's a lot to be learnt from the Internet; don't look at it as a bad thing. Would you rather be out destroying your liver by getting piss ass drunk and fuc|king random girls you'd never even met before?
Good luck