Congratulations on a new blessing coming your way! Breastfeeding while pregnant is completely okay as long as you do not have any complications during pregnancy. Just continue to latch your little one. You may take supplements or eat galactagogues but it is not a guarantee that it will increase your milk. Breastmilk is supply and demand. The more you let baby latch, the more it will produce. You can refer to these sites to learn more on breastfeeding while pregnant and after you give birth, you can now experience tandem feeding
Your body will carry on producing milk while you're pregnant, so you suould be able to breastfeed. Breastfeeding during pregnancy is okay if your pregnancy is going well, and you are healthy. Perhaps you can consider taking milk boosters that are also beneficial and nutritious for pregnancy. For example, oatmeal is good for producing bm and it is a food that pregnant women eat for energy. Milo (Australian recipe) is known to be a great milk booster and alot of pregnant women drink milo in place of coffee.