A few years ago, I went from 336 pounds to 277 pounds in 3 months with nothing but diet and exercise.
I haven't taken any medication for diabetes since then

Besides feeling better about yourself... the most important thing is that your diabetes is starting to get under control. Be careful though and make sure you take whatever supplements they instruct you to take.
Also, if you don't change your eating habits... you'll gain the weight back in a few years so be VERY careful. Consider this a new lease on life and make sure you don't mess it up