Alright so I'm going to be askin for any tips you older, more experience guys and gals might have... but first I'll give you a little background behind my habits.
So I'm a junior in high school, turn 17 in 2 days

and just signed up for my classes for next semester. My GPA is a 3.6 and I'm currently taking:
Spanish 2
Honors Physics
Honors English
Honors Chemistry
Algebra 3
AP US History
I'm not having a horrible issue keeping up with it right now, but I'm also working 30+ hours to buy a new camaro.
So here's where my issue is really starting to come into play. On top of all of those classes I signed up for an early morning weightlifting class to stay in shape for the our Varsity Tennis season (starts in April). So I have realistically drawn this out, I will go to school from 5:30 until almost 4, and during Tennis I'll be there until at least 6. this gives me an hour after school, plus an hour or so when I get home from work. Now in this block of a couple of hours I'm having issues with not being on my computer for that entire time (C5 for the most part

). for right now I need some advice on focusing.. and I know most if not all of you have or are going to college and may have some random methods you used.
As for the future.. well hell I may need more help than I can ask for as I am planning on going to Med school

any input will be appreciated, but I have an odd suspicion that the majority of my responses will say something along the lines of "lose the job and focus on school" but I have to pay for everything myself in my family. I pay for gas, insurance, food, etc. and need a job so that's out of the question.
Thanks again everyone