I know a lot of people (myself included) got into the field by turning a hobby into a career, but I don't think it's healthy to try to force yourself to spend 12 or 14 hours a day crunching away at the keyboard. Even if you truly do love programming.
Honestly, my advice is to find other hobbies and interests to do outside of work that are not programming related. Recharge during the week and use weekend time to work on side projects if you feel up to.
If you are feeling burnt out by the daily slog, I don't see how forcing yourself to "be motivated" to do more work will help.