I got a BFN on Weds last week, but DS (17mo)had been really clingy to me all week, wanting lots of cuddles, not wanting DH at all (usually just as close to both of us). Got my BFP on sat and he's still the same, almost as if he knows. Is it just a coincidence or do babies have a 6th sense for this???
Incidentally, the cats have been exactly the same, all over me wanting fusses since last week!
Short answer (imho) - yes. I found out I was pregnant with dc2 in Feb. Dd has just turned three, and she was the same as your ds - clingy, cuddly. And she came into bed with me one morning before I did the pregnancy test and asked me for some 'doodie' although I stopped breastfeeding at 22 months and she literally has never mentioned it since then then (i.e. over a year). I think little ones are pretty sentient about this sort of stuff.