Pain in lower stomach?

Hey everyone. I'm a lil over 15 weeks and today my stomach is just feeling heavy. I know that's normal. But my lower stomach is painful today. When I breathe out all the way it causes me sharp pains in my lower stomach. When I stand or walk it's uncomfortable like my bladder is full but it's not. If that makes any sense? Has anyone had this? It's nothing like the round ligament pain I get. I'm waiting for my ob to call me back..