For the last week my 3yo has been vomiting at night, sometimes following a noxiously dirty, runny nappy. This has happened each night before preschool (3x a week) and on Saturday night before what she knew was going to be a very busy Sunday. During the day she is happy, spirited and has few complaints (besides the usual demands for ice cream and lots of Peppa Pig). She has no other symptoms of sickness. After throwing up she is absolutely fine and goes straight back to sleep.
Other info - we have a 7 week old baby who she adores, but who obviously is taking some attention away from her, and she has recently moved to the preschool class at her nursery where she is being slightly bullied by an older boy and girl both of whom she really admires.
Any advice in how to understand this? I really don't know what to do.