In addition to the other posts above... you need to get started with a P.O.A. - Plan of Action.
And I am not talking about "I want to work out often and lose 10 pounds" either

I am talking about a walking mission statement. You should be able to write two paragraphs about your plan. It should answer questions like:
- What is my definitive goal?
- When do I want to reach this goal?
- What hurdles may I come up against?
- What will I do when I reach Hurdle A? Hurdle B? etc
- When am I going to start this plan?
- How will I know when I have reached my goal?
- What is my detailed workout plan?
- What is my detailed nutrition plan?
etc... Sticking with anything in college is hard. Unless it's naps in the afternoon

But you can do it. Once you start seeing results you will stay motivated. In your case it may help to have a trainer work with you. This makes some people stick with a program because they have someone to answer to
Talk with trainers at your school gym. Talk with budding fitness/nutrition students. Make friends that want to workout with you. Hire an online personal trainer. Grab a book that delivers a program for you. Decide that today is the day. If you don't get serious about it now... when will you? In a few years you will be SO busy with a rent, career, dating, gas bills, car insurance, meetings, walking the dog, etc.
Start now and make it your lifestyle. Do activities that you enjoy. Like to hike? Do it. Like to swim? Do it. Hate the elliptical. Don't do it
