Nothing is worse than getting half-way through the semester only to deal with a health problem that could have been addressed.
Get a check up! Make sure you are up to date on your annual physical. Don't forget the dentist. (I put off a routine filling too long and it became a crown - which required me to go to the dentist twice instead of once)
Get a vision screening. You can't believe how small they print textbooks these days! Whether it's looking into a microscope or reading footnotes in a literature book, you need a good set of eyes. If you've been putting this off, now's the time to go.
Invest in a good backback. Make sure it has good support and do not carry too much at one time. This may mean going to your car between classes but it's worth a little power walking to save your back. Some students like the rolling kind but these can be difficult if you have to negotiate up a lot of stairs. (learn more about backpack health)
Drink plenty of water and eat wisely. Water is the building block for all body functions. By the time you are thirsty, it's too late, you are already dehydrated which can result in sluggishness. (healthy snacks)
EXERCISE - You've heard it hundreds of time but the very exercise you do not have time for...will actually increase your overall energy level. Most colleges have fitness or workout centers. The cost for joining is a very inexpensive compared to private clubs. Look at Paradise Valley Community College's fitness center to get an idea of what they offer.