I just go to the gym, even if I don't want to. I get in the car and make myself go. Creating a habit is hard work - there's a lot of resistance against it. You just have to remind yourself that you're in the process of creating a habit and you have to be annoyed with yourself for now.
And it's all about perspective. See working out as part of getting ready for the semester

See working out as a great way to clear your mind for 1/2 hour so you'll be more receptive to information you study for your finals.
And remember your goal. After working out, go to the fabric store and figure out which gossamer you want to use for your Size 8 Chii costume, and be happy that today, you took one step closer to that goal.
Eventually, it will become habit, even if it's slightly inconvenient. I used to pick up my boyfriend from his lab every day at 5:30-6. Now, he waits for me to get done at the gym. He gets more work done, I get in shape. It's a win-win