I think you're setting the bar too high. Seriously. I took 6 years to graduate with a BS in Marketing. And it was the best 6 years of my life! College can be awesome, if you don't bury yourself in homework and studying. Take...your...time! After college is over, the sh***y part of life begins...the real part!
Lower your standards and expectations (or at least the time frame you expect to accomplish everything in)! I mean, you can still attain what you're out to get, just do it slower. Enjoy this part of your young life, for it won't be long until it's workworkworkworkwork!
To recap: Do your best on the test tomorrow. Test scores count for a lot! Next, get into a great college. Finally, get the degree(s) you want. But take your time, kid! Time only flies while you're in college. Afterwards, you'll look back and wonder about a lot of things. I look back, but I don't have many regrets because I took my damn time and had a great time! College is not to be rushed...enjoy it!