Here's part 1 of a series of articles you might find helpful: www.sparkpeople.com/resource/motivation_ar
Also keep in mind that a workout doesn't have to be hours long in order to see results. Start with a small goal such as 10 minutes of exercise each day to help you get into a routine and become consistent. Even that small amount can give you a boost of energy and help you feel better.
Good luck! You can do it!