No, I haven't taken leave of my senses!
I have two cats, one of which isn't very affectionate, particularly towards me. If I am at home during the day (I work from home quite a bit), I barely even see her. In the last few weeks she spends all her time snuggled up to me, resting her head on my stomach with her ear firmly pressed up to where the bump will be. Sometimes she even licks my stomach.
I've been reading about how cats are capable of picking up on hormonal changes, and so she probably does know what's going on. My other, more affectionate cat is a bit thick, so he hasn't worked it out yet.
Has anyone else experienced this with their pets?