Big big hugs hun! I go through this about once a week (gosh I sound like a bad mum!) so I know how upsetting it is.

I just walk the halls with him in my arms saying soothing things and patting his bum. Sometimes some calming music helps, but not always. Eventually he gets tired enough that he goes to sleep PROPERLY, but it can take some time. He will doze off many times, but not be sound asleep. It's awful listening to him cry, but it's all you can do. Or just keep her on the breast, it will usually work eventually Rest assured, if one thing is certain, it's that she can't stay awake forever, she will have to sleep sometime!

I hope she goes to sleep soon hun!