Supply drop?

Okay so I am 8 months PP. I pump once each day before bed and usually get 4-5 oz in 20 minutes. The past two days I have gotten less and less. By quite a bit. I did switch out some pump parts, so maybe these parts are less effective?

We also started trying to conceive this cycle. Is it possible I am pregnant and already seeing a supply drop? I am like 9DPO, so that seems very quick to me. 🤦‍♀️