Aww Poor Lily, and you. I hope it's nothing serious, and she's back to herself soon. Could she have eaten something she shouldn't have? Sending love hugs and prayers to you and Lily. Maybe she just has a little tummy bug, or upset stomach.
At least you have a vets appointment just in case she's not feeling better tomorrow. Keeping my fingers crossed, that she feels better soon. Please keep us posted on how she's doing. Feel better sweet Lily.