Sleeping issues

So we recently just moved our baby out of the bassinet into the bigger area in the pack n play. Ever since we did this our baby hasn’t been sleeping well. Did anyone else have this issue? She went from sleeping 8-11 hours to 4-7. I also did just read article about the 4 month sleep regression...is this a real thing? I’m having a hard time knowing if she’s just waking up or should if she’s waking up hungry. Sometimes when she wakes up I will try to put her back to sleep but it usually take a while and then she only sleeps for like 30 minutes then is crying because she’s hungry so it wasn’t really worth it. Is she hungry every time she wakes up? I don’t know if anyone else’s baby does this but she also has a hard time keeping her arms and legs still...I have been having to hold her arms down gently just so she can get settled back down to fall asleep. She’s constantly moving....especially her arms....should I go back to swaddling her...? She slept better when she was swaddled but was that because she was littler...?