No I'm going to win.
I have a different piece of advice, actually. I was like you. 4.3 GPA average, 2300 on SATs, highest rank of AP scholar due to some 12-14 tests or something and 5's on all but two of them (which netted me 4's). Same bullheaded "I can do anything and everything!" attitude, and so on. This was all at one of the top-ranked high schools in the US, which people from all over the world called and asked how they could enroll their kids. I also ended up getting some large chunk of the school awards at the end of the year, and placed in the (low) top 10 of the national French competition three years in a row.
I speak 3 languages well and have studied some 5, play two musical instruments (one well enough that I was accepted into a professional-level youth symphony), did hundreds of hours of community service in the form of tutoring. I taught Japanese exchange students history in their native language, as well as children with all kinds of learning disabilities. I also revived and headed the Japanese Culture Club, and gave lectures on culture and literary analysis twice per week.
I did not get into Harvard, Princeton, or Brown--the only Ivy I managed was Cornell. Do not be disappointed if you do not make it into the school of your dreams. Do not be disappointed if they don't think you deserve their money, because you didn't have quite enough merit; do not be disappointed if they don't deem your story sad enough. You have not lost at all if you don't quite make the bar you were aiming for. There will be other challenges and other victories to fight for, other competitors, other dreams to follow. Don't let one "failure" taint you.
I realize I'm making an assumption as to which schools you want to attend, but every other time I've heard "highest colleges" it meant the Ivies. Please also note that I've toured in all those places and, by and large, the people attending/touring were not the sort of folks I'd want to study with. Let's just say that culture can often be more important than prestige.
My other piece of advice is this: don't go all-out on academic subjects at first--you'll be able to pick those up easily. Make friends and learn how to cope, because that's something you seem to need to learn (based on your reports of extreme anxiety--trust me, an Ivy-level university will make that a lot worse) and it's
at least as important in the long run. Don't lock yourself in your room and never come out, like I did. Don't get discouraged by a jerkass roommate and hallmates, either, or by the occasional uncaring professor. First and foremost, you've got to realize that you have far, far more control over your circumstances than you used to--and then you've got to figure out how to navigate your new world.
I wish you the best of luck. Don't be like me.