Hello mommas! Desperately need breastfeeding advice!!

Im 36 weeks pregnant, unfortunately my husband and I separated so ill be having to go back to work sooner then I'd like to as I was self employed and won't be getting Maternity leave. My question is... with my other two kids I had milk supply issues...not sure but I never ended up figuring out why and could only breastfeed about a month.

This time I'm really really wanting my baby to be on breastmilk. BUT I'm wondering...how to establish a good supply before I go back to work (i'm only taking a month off) before I start pumping exclusively... or can I pump while breastfeeding ? Im so unsure how to go about it. I bought a good pump medela and I just want to make sure she gets breastmilk. Should I breastfeed and pump from the start? And freeze the pumped stuff? Should I only breastfeed at first? Or should I exclusively pump from the start? Plus my ex is going to want to share time with her.... how am I suppose to exclusively only breastfeed for a month if he wants her too sometimes 😐 I'm feeling overwhelmed but really really want to breastfeed or pump for her. Please any tips is appreciated!!!