Is this a normal amount?

I'm 7 days postpartum and I've been exclusively pumping since by daughter was 5 days old. I'm pumping every 3 hours with the exception of one 5 hour stretch at night that I let myself sleep for. I'm only getting about 1 oz in one breast and 1.5 to 2 oz in the other each session(2.5 to 3 oz total. I'm pumping for approximately 25 mins minimum each session.

I feel like if I pump more often I'll be chained to the thing all day long but I'm concerned I won't produce enough to keep feeding my daughter or build a freezer stash. She's eating 1.5 oz per feeding currently.