Congrats. Sometimes, when they are newly hatched you'll get one that somehow manages to flip itself over before getting used to it's legs, but a lot of times it can be a sign of a more pressing matter. A good share of the time it can be caused from spraddle leg. Once you feel comfortable enough to flip it back, look at it's legs. If the leg(s) are out to the side instead of under him, then that's probably what you are looking at and why it's ending up on it's back. If the legs look ok, but it's head keeps going up and back throwing it off balance, then you are possibly looking at wry neck, also known as stargazing. Both occurrences have treatment.