I fear that I was only admitted to college because I'm black.

Claim your spot! You definitely earned it and you know how to work hard. Do all the work-smart things you can to prepare and keep up with your school work. Remember to tell yourself everyday that you have as much right to be there as anyone else and you are going to make it. Doubt is a liar. Make sure your positive, useful self-talk is louder. Congrats and be to you!