Can animals sense pregnancy before you even know?

Just wondering if any of you have had experience with your animals becoming extremely affectionate and clingy towards you.. at any time, then founding out later on that you are pregnant?
I am waiting to do a test (because I'm alittle confused in the cycle side of things at the moment) but I've been having weird symptoms lately. although, I am waiting to test. 
But in the last two weeks my two female dogs have become insanely clingy and under my feet constantly, have been extremely affectionate & can't even go to the bath room in peace & very sooky. 
Now, my mothers cat (that I could not even pat with out being attacked) has been all over me in the last few days. 
Just wanting some stories & to see what you all think. ?
P.s not sure if I've put this is in the right topic category.