Daisy seems to be better. We had made her a vet appointment this morning for 2:20 in the afternoon, but by 1 she seemed to be better and back to her normal self! So we are just keeping an eye on her, and if we suspect anything is wrong again, we'll definitely take her to the vet.
Thank you for all your replies on this, I really appreciate the support and the help! I've learned a lot from this.