A.K.
I feel for you, it is so hard to force yourself to go to work when you know your kid missing you bad. A couple of books we read to prepare for a daycare switch:
'Adam's Daycare' and 'Llama Llama Misses Mama'.
Maybe you could ask the teacher if there is anyone she seems to connect with or would be good for her to be friends with, and meet that parent and ask them for a playdate outside of school. If you reach out and let that parent know you kid is having a hard time adjusting, I'm sure they would do anything to help, I know I would. We have all been there at some point.
Stay positive and encouraging. If you coddle and let her know you are feeling guilty or sad or panicked, she will sense that. A lot of "you'll be ok, you are such a great kid I know you will find some friends", and "you're doing a great job at ____ and ____, you'll feel more comfortable in no time at all", and "I'm so proud of you for ____"
GOOD LUCK and hang in there.