16 week old moved all night

My 3.5 old was sleeping sooo well wince birth but we recently moved her to the pack n play ro get her used to her crib soon. This is night 3 and she discovered sleeping on her side which is fine but she constantly rolls back n forth trying to get on her side and then cries for her pacifier when she losses it. She does this ALL night! I think I've lost it! I don't know what to do she settles for 30 min then back to nusiness5.do you think this is a sleep regression or do you think this is her trying to get used to laying on her side? Heeelllppp