nipples leaking maybe?

I don't even know if I'm pregnant. I do know however I have almost every symptom there is and I'm 2 weeks late. I've taken several test and all say negative. I have an appt with the dr next Wednesday to see what's going on. I've "calculated" how far along I am and it said 6 or 7 weeks. Anywho. My DF was just sucking on my nipples and said he felt something come out of it. Can someone explain this or have anything like this happen?? Sorry if tmi