My baby will only go in deep sleep if he has enough milk. He is turning 7 weeks in a few days. If he has not enough milk, he will fuss and can't sleep well. Then occasionally we just give him a little more milk just to make him happy. Don't follow strictly to the feeding schedule. Also has to make sure he is comfortable.
My advice, make sure Ur baby is fully satiated. As they grow, their intake increases so u have to keep that in mind. And it's normal for them to fuss alot when you put them down. These babies are so smart they know when u no longer hold them. It's a natural feeling to want to be held. It is said babies don't know they are a separate person till they are 6mth old so they love to be held and cuddled all the time to feel safe.
Only worry if your babies cries alot during the day then probably it's gas or colic. She just wants her mummy.
sthj