Cat drooling

Yesterday when I came home from work, I noticed my 2 y/o cat salivating and dripping all over the place. It's not a ton of drool, but it's not normal for him. He's still doing it. Has anyone had this problem before? I am freaking out! Otherwise, he is acting completely normal. Using the bathroom, eating, drinking and playing. Could it be from anxiety? We just found out I'm pregnant. I know animals can sense that stuff. Let me know your opinions/experiences!