There are a couple of things that can drop supply - being pregnant, and taking sudafed.
Otherwise, get bub's ears checked, try feeding in the dark, try giving her something to play with whilst feeding, try hand-expressing a tiny bit before a feed so an impatient bub doesn't have to wait and feed her often.
When you start solids that can do funny things too until she gets the hang of solid pooh - but again frequent bf is the best thing for that as well.

good luck.