Unable to pump anything unless baby is on other breast

Amanda • Boy mama💙Gestational Diabetes🍩Ectopic January 2018👼Previous mild hydrosalpinx 💉

Help Mamas!! The only way I have been able to pump so far is by feeding my baby at the same time. If I try without, I cant seem to get a letdown. Worried that when I go back to work I will not be able to continue pumping due to this issue! What can I do??