How do you increase your milk supply?

Y
I'm not EBF bc I don't make a lot of milk. At most I can get 3 oz together from both breasts. I've tried brewers yeast and mothers milk. However, this week it seems I got my period and I'm only making about 1-2oz. What I can do to get back to the 3oz or more? (I have a pump and I breastfeed when I'm home. Going back to work Monday 😞😞)