S.S.
You need to say very firmly to her mmmy is going to school I will be back at x time and go. don't do the long drawn out goodbye so sorry I have to go etc. just walk out the door. she will get over it. I used to have daycare parents who would say to the kids "I am so sorry I have to leave you here" wth whats wrong with my house? it gave the impression that something was wrong to the kids. You little one is doing this because you allow it. Just say goodbye and go. she will be fine. Don't throw in the towel. it will be good for her to get a little bit of independence.