Hi Yvonne, 5-6 diapers a day seems ok to me.
There would be other signs if yor baby wasn't getting enough to eat. They woul be fussy throughout the day and keep wanting to feed.
It it rather normal for babies to prefer one side.
Some suggestions would be to try a different feeding position for tye other side.
Either lying down or football hold. These worked for me when my baby had this issue.
Read more