Losing Weight After Anorexia?

I need help trying to understand why it is so difficult to lose weight, and if my metabolism is permanently messed up! If anyone could give me advice on this, i'd greatly appreciate it ..So I've been physically recovered from anorexia and exercise bulimia for 2 years now. I went from being 103 lbs to 155 in less than 4 months of recovery. I have been hovering around 150 these days, and I'm finding it extremely difficult to understand how to lose weight properly.. I am currently maintaining on just around 1400 calories a day, and I'm wondering if this is enough?Should I raise my caloric intake so I can have a higher maintenance number?

Because it would put me under 1200 calories if I were to burn off 500 calories per day, and i have a feeling the weight loss will plateau quickly and my body would hold on to the stored fat for dear life.. that's exactly what I don't want. What can I do to raise my maintenance calories and still be able to burn enough to lose weight?