You might need to do sponge baths for now.
She probably just needs more time to get settled in.
You might try feeding raspberry leaves. It's supposed to calm mares down a bit (and some people use it on geldings), so it might help with her. It takes about a month to get into her system. It works very well on my mare. Everyone knows when I run out of raspberry leaves!
You do need to give a few months off of them during the year, but I usually do that during winter, when she isn't as crabby. I buy a 1lb bag from herbco.com for like $10, and that lasts a decent amount of time. My mare gets about 1/4c-1/2cup a day.
(Mare Magic is the same thing, but it's way more expensive and the dosage is way too small).