my baby girl is never full !.

Gousha
Hey guys. My baby girl is almost 2 months and whenever I breastfeed her she's never full and she's always hungry and cries whenever I leave her. And I started using formula since 2 weeks ago because I don't have any time to pump my milk and I only give her formula at night and whenever we go out. So I can have sometime to relax and sleep But I really do wanna breastfeed her but she never seems to be full. Any tips and advices for a newly mother ?.