When did you stop breastfeeding?

Corey
Is there a time when it's okay to stop once I've started breastfeeding? He gets one bottle of formula to top him off sometimes already. And formula when people watch him. He's only three weeks now, but I'm starting back work three more weeks and I can't pump enough to have other people feed him unless it's formula. I feel terrible because I want to breastfeed him as much as possible but the pumps don't get as much out as he does.