Body not responding to breast pump anymore?

So I’m having some issues with pumping lately, about the last two weeks. I have 11 week old twin boys that I BF and pump for. I’m fairly certain that my supply is okay because I primarily BF and the boys seem to be full and satisfied after 🤷🏻‍♀️. I used to pump 5-6 ounces but lately I’m lucky if I get 2-3. Even if it’s been a while since I’ve BF. I’ve replaced the membranes and diaphragms, tried different flanges, played with the speed and suction settings and nothing seems to be changing it. I haven’t tried a manual pump yet. Is it possible your body can stop responding to the pump?