What Can Cause Increase In Breasts Size?

i have noticed in the last 2weeks that my breasts have started to grow looking fuller, yesterday i notice that a very tiny amount of clear/cloudy fluid leaking out from my nipples, my breasts and nipples have been sensivive for about 2 weeks but i have taken two pregnancy tests which where 5days apart and both said negative so im a little confussed about why my breasts are leaking. the liquid coming out from my breasts does look like the first bit that devlopes when pregnat so i am thinking that it is breast milk (i have a little boy who is two which is how i know) i feel some sickness certain smells like cooking chips makes me feel sick but the tests said im not? also i have not missed one of my pills but did get taken off of them 2months ago and put on a tablet to stop any bleeding as my period were irregular but have been on my pill for two months now and my last two period where like nothing basicly i blead for about an hour both time.