Sounds like she is egg bound, I'd start with letting her float in some nice warm water. sometimes that can make them relax enough to lay, then if that doesn't do it you can place her in a warm place on a lowest setting heating pad with a thick towel wrapped over it so she lays on top the humidity from her own body and the pad can help create an area that can help. Sometimes you can lube up your finger [no long fingernails] and try and feel it and see if you can gently work it out. None of these are a guarantee but worth trying. giving her some type of calcium gluconate or calcium citrate in her water can help too.
Hopefully others will share what may have worked for them.
I thought I had an egg bound duck and did all the things mentioned above.. warm baths three times a day as well, calcium and other vitamin supplements added to water. I'm sure if that was my ducks problem it would have helped... you can't always feel an egg, it may be up too high(lubricate well if you do try), so don't be alarmed if you can't feel it. My duck was just sick though.. but presented with typical egg bound symptoms at first.