Hi. For this age, as you mentioned you just newly enrolled her in playgroup, it is very normal to experience separation anxiety as it is a big transition for her. When a child feels anxious, she/he can't sleep well, that's normal too. Just show her extra love and reassurances during this period of time to let her know that even though she's going to school, you are still here for her. I'm sure she'll grow out of this phase soon. :)