I'd try to do weightlifting besides kickbox. I did kickbox and it's like HIIT with bodyweight. It's a good fat burner if your diet is clean, but weights burn even more.
This happens to girls. I had something similar after strict dieting in highschool. Eating like a normal person led to fat gain. Small amounts of food led to anemia. It's sort of a damned if you do damned if you don't. Things changed for the better when I started lifting heavy.
And there's also the aas alternative. On aas, I ate like a man.
“The thing women have yet to learn is nobody gives you power. You just take it. ” - Roseanne Barr