Just take it a day at a time and don't think about the stretch ahead of you. You may "only" have a stone to lose and a month of Cambridge ahead of you, or you may be like me and looking at nine months on the program. The time soon starts to fly, and you'll be amazed at how quickly the numbers fall. That, in itself, is the biggest motivation you could have.
Try to understand how you became overweight. What was your eating pattern? I ate for every reason: taste, boredom, loneliness, as a reward. Consequently I've had to learn new behaviours (and am still learning... it's a long process). When I'm bored, I do some volunteer work or exercise. If I'm lonely, I come on the forum. If I deserve a reward or treat, I have a bubble bath with an expensive bath bomb from Lush. If I want something delicious... well, I'm kinda screwed there, but three out of four isn't bad!