Super overwhelmed and emotional

Hey guys, im in the early stages of my first pregnancy (4w3d) and my emotions are all over the place. I am so happy im pregnant but i cant help but feel bursts of sadness for no reason and i just start crying. I am feeling overwhelmed soooo easily, any little inconvenience is triggering me and making me feel all sorts of things. Angry and mad and worried and anxious and im always so soooo tired and fatigued. Is this normal? Why am i crying if i am happy to be pregnant? Its making me mad, i feel crazy. It's affecting my productivity at work. Help