Sounds like baby has gotten more efficient at emptying the breast and that’s why you’re getting less when you pump after a feed, when your supply regulates and baby becomes more efficient this is normal! You can try latching more often to increase your supply, or try power pumping if you’re trying to build a stash. Make sure you’re well hydrated too :)
Sounds like you need to a pregnancy test Same thing happened to my supply and breast were sore .. turns out I’m pregnant again!!!
It can take a few days for supply to recover after a blocked duct I've found. You're doing the right thing, keep latching baby and pumping as you normally would, some heat applied when you pump can help get things flowing I found. Try not to stress as that won't help, or pumping too much which could trigger the inflammation again.