Is fearr duit bheith i d'aonar
"I'm off" used in the sense of "I'm heading out now" would be 'itte kimasu' if you're leaving your house/a place where to which you will be returning. When leaving work, you would say 'osaki ni...
You may say 'Hayaku shita hou gai ii,' among others.
ほっといてHottoite