@turkishdeelitee - hopefully you will be able to come back to the thread and find the good advice you’ve been given - like letting her have ham if that’s all she will eat, because UPF calories are better than none.
Sticking with what she will eat will help you too, I think - if you feel that she is getting some nourishment, even if it’s not ideal, that may help you worry less, and taking the worry and stress out of the whole situation for a while may give you both the break you need, and later on, she will start to widen her range of foods.
That said, I really do understand how difficult it is not to worry about something as fundamental as feeding your child. I had major problems with breastfeeding - in fact, ds2 ended up in hospital with a chest infection, but when he was there, they said that he was failing to thrive, because at 6 weeks old, he hadn’t regained his birthweight despite me feeding him almost constantly.
In fact none of my dses ever gained weight until I started formula feeding them, and I felt like the worst failure as a mum because I literally couldn’t nourish my children. But I learned to look at it as a phase, and as a part of parenting, not the be-all and end-all - and now they are all healthy, flourishing adults.
So I do understand that saying ‘don’t worry’ is easy but doing it isn’t - I hope you can find a way through it.