Focus on school and academic achievement. Also, look into volunteering abroad, it's a great time in your life to do that. Exercise and focus on fitness. Make grand plans for career or grad school. See your friends, but for lunch or coffee...and make new friends to add to the ones you have.
20 years down the line, these are the things you'll wish you had done in college...I'm not assuming you aren't doing any of this, just that these are important things to focus on rather than bars.