You need to get Milly to a vet. You must understand that not everything can be fixed at home. Her symptoms are very vague meaning that anything can cause them so it's impossible for us to offer advice without knowing the underlying problem. When you take on a pet it is your responsibility to get them care when they are sick.
Dental issues are very common in rabbits so she may have a problem in her mouth making her not want to eat. She could have a virus. She could have a problem with any of her internal organs. I can't say. While you are trying to find a vet for her all I can offer you is that you try to force feed her with this critical care diet.
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https://www.amazon.com.au/Oxbow-Critical-Apple-Banana-Supplement/dp/B001FKACXO/ref=sr_1_1?crid=2ADWE5MWOJJKA&keywords=oxbow+critical+care&qid=1560514875&s=gateway&sprefix=oxbow+cr%2Caps%2C814&sr=8-1 )
If you don't know how to force feed there are many YouTube videos available for you to watch on how to do it. I hope it helps but she really does need to see a vet. Hope this helps. Best wishes.