How many calories per day?

I was told by my nutritionist that I should only start counting calories when my weight loss completely stalled. When I log my food I tend to eat more because I look at the list and think, jeeze, that isn't nearly enough food and end up eating something right before bed that I probably don't need. Even then I was consuming approximately 900 calories. I was told that once you reach your goal weight you should be eating at least 1200 calories.