I haven't gotten there yet, but I do know it is harder to lose weight when you are closer to your goal. You can't expect the same 1-2 lb. a week loss, but about 1/4 - 1/2 a lb. a week. Your body does not require as many calories to function as it did when you started. Also, sometimes your body gets really comfortable at a certain weight and doesn't really want to go below that, making it harder.
As for changes, do you strength train? If not, adding that in will help to speed up your metabolism over time. Try not to stress too much about it though. With patience, you will get there. It will just take longer than before.