First time pumper

Baby is four days old today, we’ve been kinda/sorta breastfeeding and have decided to exclusively pump. My milk came in yesterday morning and my breasts are huge and hurt a lot. I’m pumping every three hours for ten minutes on each boob, I know there’s more in there but I’m wondering if I keep up my pumping schedule will my body regulate itself? I don’t want keep pumping anymore than I am because I’m worried my body will just keep making more

I want enough to feed her, but my boobs hurt so bad I can’t take upping my supply. I need to know how to get milk out and relieve the pain without telling my body to make more than it is