I remember that awful heavy gut feeling in the pit of my stomach over a similar situation that happened almost 3 years ago. It sticks with you too. For your own comfort what I would suggest is stay at day-care, or visit just before her naptime. Most centres have an area you can hide to see how your babies are coping. Are you able to do that? Maybe your baby is different when you’re not around. I know my daughter is. See for yourself what happens. Also try getting her to favour a naptime only cuddle toy at home. Make it smell like you, take this everyday to day-care so that she can relate that particular time of day to sleep. She may just not want anyone else so the toy is a great way for her to comfort herself.
Good Luck