A.D.
It's one of those things that is not mentioned very often about pregnancy but I had that problem. It's typical, as mucus production increases during pregnancy and your sinus passages swell up more since your blood volume is increased. It wasn't as bad with my second son as my first son, the first one was a December baby the second one a late July baby. I figured out the better I hydrated myself the better off I was, it was easier for me to remember to stay hydrated the second time around because it was so hot. So drink more water, add some lemon or lime to it to make it more palatable and you can try a Neti Pot, it might help or even just saline to help soothe and thin things out.