I'm seeing that your average more than a 2000 calorie burn. If you want to maintain, eat as much as you burn.

See another doctor and then a 3rd. It could possibly be a kidney issue or some bone marrow condition. Do you drink, even a little? Stop that until things are worked out. So too with cigarettes. Cut back dramatically on sugars and carbs - which can effect the liver and how it works with proteins as well.

You can consume a "normal" rate of calories, don't need to increase, especially bad calories. Weight training (resistance) will give you strength to lift more heavier weights - after a while with lifting heavy weights, you will gain muscle mass and the numbers on the scale can increase.