Try legendairy milk supplement. Heard alot of good reviews about it. You can try the "bestseller lactation support bundle" from legendairy milk. Its like a starter pack, 3 type of supplement inside, see which suits individual best. Its totally natural and safe to use. I will be using it too after i birth my baby in 6weeks time.
Below article may be useful to you. https://sg.theasianparent.com/how-to-increase-breast-milk-supply