Or she drank too much too fast and overfilled her crop, thus the 'throwing up'?I am wondering if she got sick because it's close to 100 degrees out and she didn't drink enough water the one day. That's the night she was shaking a little bit.
Not sure about ducks but I give my chickens an occasional dose of electrolytes to help with heat stress.
I give a dose of Sav-a-Chick electrolytes/vitamins about once a week during heat waves.
It really seems to help....started this after they saved a heat stroked hen once.
Can mix up a smaller amount, just wrap the packet tight and store in a dry cool place.
Always have plain water available too.
... She looks like a monster!!!
Poor Gil. She's getting some extra swim time and hopefully she'll look extra cute for pics after this molt! How long do they usually last? This is her first real molt and she's a little grumpy. (surprise get ready, next Saturday is her first birthday!) So will she be ready for her party in time?! 
