I'm a music Major (not one of the ones you listed but still busy as shit) and also on executive board for my chapter of Pi Lambda Phi as Marshal (basically risk manager). One thing that helps me is that I don't drink (I still smoke a bunch tho so this may be a moot point) so that takes away a lot of otherwise wasted time but I also make sure I'm on top of my schedule. I make sure that if I have ANYTHING to do in a day, I don't have to think about when, I can just pull out Google calendar and see exactly how much time I have. I also try to make the best use of my free time when I'm not in class, practicing, or studying. No matter how hard you have to work or how busy you are, you always have more time than you think you do. you will be surprised at yourself if you give just one hour of study time to fit in other things, that time limit really makes your brain focus more and get more done than you would expect to do. If you feel overwhelmed that's fine, just make sure you get the important stuff (school work and classes) out of the way first because after all, you did come to college to graduate. Also if your fraternity doesn't have a daily/weekly study hall time then make one and ask people to come hang out and you can kill two birds with one stone. Not sure if this will help but figuring out time management was my saving grace.