Your calories were really low which certainly has an effect on metabolic rate. I had lots of problems coming off a low cal diet. If I were you, I would make my changes very gradually, bringing up calories slowly, and monitoring how you do. The scale is not the best measure for body fat unfortunately. Also, heavy weight lifting is the best thing you can do for your body composition. This will increase your metabolic rate and eventually allow you to eat more.

It's great that you are feeling good. Hopefully you will be able to bring up your intake without too much more weight gain.