I have one of these too, she will cry if someone walks past her, she will cry if someone gets their lunch/snack a second before her, she will cry if the older kids jump and run, she cries when she has to go for a nap (even though she's falling asleep on the floor while playing), she cries when someone gets dropped off. Took me MONTHS to get it to stop. At first I did all the 'oh its ok, your fine, and blah blah' but that seemed to make it worse. So then I went to using my 'not so nice daycare voice' and told her firmly to STOP! We don't cry for no reason at daycare and then removed her to the playpen away from the group. Then it went to, just removing her the second she cried over nothing to the playpen without saying a word. Now, 6 months later I just have to look at her with 'that look' when she starts and she instantly stops.

At home, she cries, she gets whatever she wants...really hard to get them to understand that doesn't work here but be consistent and persistent and it will hopefully stop for you too. Now she's an adorable little girl who everyone loves...but it took a while for sure!