I have the same problem with under eating if I "follow my hunger." I think I messed up my body with too much low calorie dieting in my teens. I'm sort of tall and a little active, but I would be eating your meals in addition to a pound of meat for dinner (I'm also female).
The thing with eating so little is your body decreases your energy out to make up for it. I much prefer the higher energy to constantly feeling tired like I do if I under eat, and maybe the appropriate calories/energy allows my body function as it should.
I also second Joanie's suggestion of nutrient dense red meat, offal, and fish. Lots of important vitamins and other good things you're missing out there. Don't feel the need to be afraid of fat so long as you're not drinking it, and think about your sugars (unwhole fruits/juices) much the same.
yeah, but "hey i'm Khan the sword king" is not normal.... the universe is being fickle... this is a thing... ignore me for a few weeks.