Newborn sleep... Help please!

My LO is five weeks old and EBF. She sleeps soundly in her bedside bassinet for the first four hours of the night or so, but after waking to nurse, having her diaper changed, and being soothed back to sleep, she becomes so restless in her bassinet! Her eyes will be closed, but she grunts and whimpers. It will look like she's sleeping, but every few minutes she'll pull her legs straight up. It doesn't seem like she's able to get into a deep sleep. We have her swaddled in a halo sleep sack or a swaddleme. If I take her out of the bassinet and lay her on my chest, she will sleep soundly. I'm not getting any sleep when she does this! Is there anything I can do to help her sleep better?