I'm gonna use my logic...it only happens when you pick her up from your moms house? I'd check if she was eating anything from there that you don't have at home. Wood, carpet( yorkies are very good at ripping it off
), ummm maybe a trashcan? Idk. Louis has eaten a bit of my carpet and thrown up at night..the next mornings he's fine...jumping up and down and running around
. I'd take her to the vet though, just in case.