Hi mummy, if you're already latching baby directly, your pump output will be lesser since baby already drank most of it. The best way to build supply is by latching often and pumping often, diet or supplements are hit and miss. You can try power pumping once a day as well. Good luck but most importantly don't feel bad about it, you're already doing your best for your baby!
It could be stress or lack of rest. My supply is also low. I took GNC fenugreek supplyment to maintain my milk supply. However at times I feel that it has no effect. I am trying a new supplyment. Reviews seems quite good. You might wanna consider. https://legendairymilk.sg
Do you do direct latching? I’ve noticed that when my LO latches, sometimes she can bring about 3 let down reflexes, more than pumping can. Stress, lack of sleep, illness, medicines, less frequent pumping/feeding, dehydration can all cause a dip in the supply.