Watching? If you're not counting every kcal it might be time to be more strict. I'm not saying that 1kcal is going to make a difference but if your guesstimating you may be consuming too much.
It's probably about time for you to recalculate your intake anyways. After dropping 50 lbs (high five) your TDEE has surely changed. It sucks but you might have to cut calories to keep your deficit nice and plump.