Getting baby to sleep

J❤️
Hey so my baby is 4 weeks on Monday. When we wake up for night time feedings I make sure to keep the room dark with only the night light on. I start off by changing her diaper so that this doesn't wake her more after the feeding. Then I sit in the rocking chair and feed her and try to rock her back to sleep. This ussually takes at least an hour of not longer. She is ussually just wide awake and it's becoming so difficult to get her back to sleep. Anyone have any advice on getting a baby to sleep easier? I've even tried getting her to just fall asleep at the boob but she ussually just unlatches when she's done. 
I also refrain from talking to her so I don't wake her up more. I will sing lullabys to her but doesn't help I don't thimk