Worried toddler mom of child sleeping to much

Patient: My daughter will be 2 April 30th. She was born premature at 31 weeks with her twin brother. The last 4 days she has been taking her nap at 2pm and sleeping until the next morning, roughly 8am. She will wake up about midnight to eat but goes right back to sleep. She has no other symptoms, when she is awake she is happy and plays. Should I be very concerned?She laid down for her nap yesterday at 2pm and woke up at midnight for food, went back to sleep till 6 am and is now back asleep at 10am and it is 11:06 am now as I send this. She is starting to sleep a lot more.

Symptoms: Sleepy