advice please...? :(

Cara
So recently I've been having trouble in my relationship... I'll start off by saying he's the greatest guy I've ever been with. I have tons of love for him and he's very good to me despite the little problems every couple has with each other. I'm currently about 15 weeks pregnant with his child and I wouldn't choose anyone else to be the father of my child. The problem is... I'm finding myself to be unhappy. I've noticed lately I have such a short fuse with him. Everything he does irritates me or I see as "wrong." I'm unsatisifed with our sex life which is super out of the ordinary for me. I find myself feeling sad or even sometimes crying after we have sex. And every night before bed, I find myself thinking about how nice it would be to just be alone. I don't know what to do.... I don't know if I should talk to him about it. I don't even know what's wrong with me. But for the past two weeks I've just been so unsatisifed with our relationship all together. Can someone please help?