Sudden dip in output?

so i got the momcozy m9 ahead of travel for work when i wouldn’t be able to consistently use my wall pump (i rent a medela symphony from the hospital where i delivered). mot immediately but eventually i got almost identical output with the momcozy, which is super important for me as a mom of twins - the girls sat 7-8 ounces each feed, so i have to maintain that output if not greater.

anyway all of a sudden, ive started to get like half the output of that week (or less!) or so that i was away - even pumping for 10 (or more) minutes more (sometimes i’d fill the momcozy in fewer than 30 minutes). anybody else experience that and know what to try to “fix” it? right now i’m pumping with the momcozy to try to figure out the right settings but then i have to connect to the wall pump to empty because my supply was starting to diminish. ive boiled all the parts, i always check that theyre perfectly dry, i’m wearing the same bras i wore before. im at a loss.