Pumping

Beth • 26 🇬🇧 Mummy to Elsie 19/05/19 & Tommy 18/06/22

When I pump during the night (2am & 5am), I get about 3.5oz from each side but during the day (again, every 3 hours), I’m only getting 1/1.5oz from each. Is this normal? Is there anything I can do to get more throughout the day?