If you weren't pregnant mothers milk tea would probably help. Unfortunately it has fenugreek in it which you are not supposed to take while pregnant. Also I believe I read something about flax seed not being recommended. I would ask your dr or a lactation consultant. The le leche league have a support number you can find online.
Keep nursing baby! Also look up a recipe for lactation cookies. I actually make the cowgirl cookies in a mason jar recipe and add a half cup of peanut butter but only half of the chocolate chips and m&ms. They are super addicting and oats is one thing that helps with lactation. Also brewers yeast helps and flax seed. Just Google foods that increase milk supply and you will find lots of things. But the cookies are a huge help. I missed my daughter till she was 17 1/2 months which I was 5 months pregnant when she quit nursing.
I did for three months. My daughters now a year and a half so shes on whole milk but i was going through the same thing. They have this tea at walmart that helps your milk supply n it worked really well n it was good until i started getting really emotions like a roller coster n i found out that it was a rare side effect. Also that tia and tamera thing milky i think its called they sell it online. N drink lots of milk believe it or not you need to eat for three!!!! So eat more n more n more.
Could be running low because of pregnancy. Don't supplement with formula though! Baby will bring your supply back. I'd talk to your doctor/midwife about whether it's safe for you to continue nursing. If you have a high risk of preterm labor they usually don't suggest it.
But ask if you can drink mothers milk tea and pump between feedings for a while until your supply comes back.
I'm a ftm but I've seen some posts where moms say their supply is running low because of the new pregnancy.