My cat knows I'm pregnant?

So I'm 15 weeks and my cat will not leave me alone! She follows me everywhere and is constantly sitting, laying or kneeding on me. She usually doesn't like attention, and never likes my fiance to hold her, when she does go on him, which is rare, it's usually just to walk over him to get to me lol I know animals can sense babies, but she was doing this since I was like 8 weeks. can they sense it that early? lol anyone else experience this with their pets?