If your progress has been based on diet alone thus far, just think how much more you could lose by adding in exercise! For me, I was overweight enough that too much exercise was really hard on my heart, so once I got down to a more managable weight with diet, I was able to add in some exercise and that has just increased my results!
Do some fun stuff...swimming or dancing, if you're into that, or something else that's high energy and tons of fun! Do it with some of your friends maybe, make it a group thing! It'll help keep you motivated.
Congrats on your progress, you're doing great!