Hey, don't be too hard on urself. Baby is likely to be in a growth spurt phase so can be difficult to handle and ace ur mil has been looking after, baby may prefer someone more familiar which is totally normal and alright because - hey, confinement is for the mummy to be totally as rested as possible. Most babies tend to be more active and easily hungry and cranky at night during the first 1-2 months (as their day and night perception is not fully developed - hence more fussy at night too) plus the possible growth spurt phase too.
Don't be too hard on urself. Baby has no preference one. If have preference, it's definitely the one with the boobs and the familiar heartbeat --- which is YOU!!
Relax. Don't demand too much of yourself and how things should be - it's just the beginning and u have a lot lot lot more time with him soon...
For now, rest and recover