Im on sick leave for bereavement and stress,my employers are badgerin me to go back im not ready,what do i do?

i lost my long term partner on xmas day,im not coping well at all,yet they expect me to go back to work next week,i cant think for myself right now let alone think for vunerable adults.where do i stand? i do have a covering sicknote.i will be a liability more than anything else.i do love my job and want to go back but right now im not ready.