Breastfeeding while pregnant and soooo tired

I'm really struggling to make it through the day. I nap everytime my son does and I dont know if its because I'm in the fisrt trimester or if being pregnant and breastfeeding is taking a toll on my body. I am eating a ton and trying to eat as healthy as possible. I'm chugging water by the gallon and only having my single cup of coffee in the morning like I always do. Never stopped taking my prenatal and I have a protien/vitamin shake every morning to start my day. Any tips from Mamas who have bf while pregnant? Does it get better?