A.A.
Say your goodbyes in the car. Scale back the 10-15 minutes in the school to about 30 seconds. Walk her in, give her a quick kiss, say I love you, and leave. Don't look back. Cry in the car if you need to where she can't see you. You are dragging out the goodbye and making it worse. She's playing you a little---its her job to make you feel guilty and toddlers are very skilled at it. Sticking around that long is actually worse for her, because it makes her think she may be able to persuade you to stay. I say do your goodbyes in the car, because I have had parents drop their kids off and the kid is fine and goes to play. Then the parent stands up to leave and calls the child back to say goodbye and get a kiss. This totally disrupts the kid's focus and brings that back to the feeling that mom is leaving and this is the point they get upset and start begging mom to stay. Do yourself and her a favor and make it short and sweet. She's fine once you leave and will be happy to see you when you return. I know its hard, but this is all completely normal and can usually be solved with a quick drop-off. You don't want her to start every morning off like this.