fussy 6 year old

Hi Ladies
Hoping you may be able to offer some helpful advise. I have a 6 Year old DD, who refuses to eat almost everything.
When she was a baby she had a great healthy diet i made all her baby food full of fresh fruit and veggies and meat and she generally ate it without any dramas.but since she was maybe about 3 she has been so fussy and i think its getting worse. she would happily live on processed carbs. she wont eat cereal or eggs, refuses most meat will eat ham on its own spaghetti with meat sauce or lasagna is hit or miss, only eats steak if its crumbed, refuses all vegetables and will maybe have a mouthful of mash potato if im lucky, she used to love cheese and yoghurt but now hates it, she will eat some fruits strawberries, banana apples.i can cook anything and unless it comes from a box she will refuse it. i feel like the only way i can get her to eat especially at school is to give her crap food which i hate! i have cooked healthy treats and sent lunch box full of beautiful healthy and yummy food but she will just refuse to eat, dinner is a nightmare guaranteed she will not eat anything and then after say she is starving and have either plain bread or fruit. she wont try anything knew and on the odd occasion she does she always spits it out with disgust. i dont understand becasue i offer a variety of lovely meals, mummas has anyone else gone through this? its stressing me out i worry she is lacking in important nutrients the dr says she doesn't look pale or underweight so shes fine, but i cant see how she is getting everything she needs from the very small food groups she does eat. i just dont know what to do.