If she can't keep ANYTHING down I would take her to the drs. A dry nappy and cracked lips sounds like she is well on her way to dehydration, which can be very dangerous for little babies.

Have you tried the gastrolyte icy-poles? Or any icy-pole really?
I had a similar problem this week, DD wanted to be BF but kept throwing it up. I gave it to her anyway as i figured she MIGHT get some hydration from it and the throwing up bit wasn't distressing her too much.