Fuck man, you're like in High School. Literally nothing matters except your grades UNLESS you meet someone who you really, really, really, really like and by some .1% chance off of that .1% chance you decide to marry her and she agrees. So stop being a pussy about this and trying to blame ADHD or some other scape-goat. It's your fault, and if you want change you have to do something about it. -Pick a damn girl, this isn't fucking rocket science. Flip a coin if that helps. -Study at least 1 hour a day as added to your homework. Also talk to teacher when you have problems with such and such a thing. They might help you and people tend to learn better when it's 1v1. -Eat healthy. -Don't break any norms of society and be a friendly guy. -Have proper hygiene. -Don't piss off anyone if you can help it. Do that and you'll be fine.
Focus yourself. Seriously dude, if you're failing three subjects (and by the sounds of it, almost failing some others), then something's not right. I know it's hard, but go to class and listen as much as you can. You will never be young again. You will never have a second real shot at school. If you're struggling in class, tell the appropriate teachers and get help from them after class. That's what they're there for. Don't try to hide the fact that you're failing, face it and try to fix it. That doesn't mean you have to spend every waking hour studying, far from it. But take some time every day to refresh what you've learned, and read ahead a bit. Stay healthy. Eat healthier and exercise a bit. Don't watch too much TV, play too much games, or spend too much time on the computer. I'm not saying abandon those things, but have them in moderation, on weekdays especially. Don't take any substances that you aren't prescribed. Shit like that messes up your life at your age. Be positive. Talk to your friends and socialize with them more. Pull yourself together mate, we're rooting for ya.
I already stay 2 hours after school every day. Sorry Kark but it doesn't ecactly work that way in the real world. You dont just say " I like both of em but I will pick her for the lulz! " Actually no. I am not.