Lauren, I'm so sad that Mango is feeling so grotty. I hope she does not vomit again, otherwise, you're right, I would also take her back to the vet. If not, you may have a miserable night ahead of you... not knowing if indeed this is normal or something to worry about, especially as she was so ill last year.
Please keep us updated.. we know how precious she is.
Prayers and hugs still coming.
Sheilagh