I've read a little about calorie cycling and a lot of people do it to boost their metabolism...so maybe you going over for a day or so has triggered that effect. I would go low for a day or so and then go back up again.
I guess that's my only advice....but I dont really COUNT calories anymore and I am doing better then I was when I was staying within a calorie range. Instead I am learning to eat when I am hungry and stop when I am full and eat ONLY certain healthy foods and in moderation. Its hard but stick with it