It took me a long time to get into that habit... at first, I would have to "plan" it into my schedule, and when it came time, I'd remind myself "You don't feel like it, but you'll enjoy it once you start, and at the end you'll be glad you did." Sortof mentally dangling a carrot in front of my nose :-)
I still have to do that sometimes. Also, I keep in mind my long-term goals. One day doesn't seem like it makes a big difference but it is part of a big process.
Thanks for your feedback - yeah, it feels great to exercise!