LO has been in size 5 overnight diapers for a bit now (she's in size 4 during the day). She's been leaking out of them a lot lately (like probably 4 nights a week). Should I move up to a 6? Are they going to be too big on her? They say for toddlers above 35 lb and she's only about 23. I think they fit just fine but she sleeps on her stomach the entire night and pees a lot so it only absorbs towards the front then leaks out.