I'm working right now, so I'll call you back later.
My father is at work right now, so he can't answer the phone.
I got an urgent phone call while I was working.
I try not to look at my phone while I'm working.
休み means a break or day off, the opposite state of 仕事中, which describes being actively engaged in work.
Compound of 仕事 (work) + 中 (in the middle of). The suffix 中 (ちゅう) indicates being engaged in an activity.