What Causes Leaking Breasts, Nausea And Mood Swings?

Hi, may I answer your health queries right now ? Please type your query here...My period was 2 weeks late, but I did get it (lasted 3 days). 9 days after my period my left breast started to leak what appeared to be colostrum. So between the mood swings, heartburn and nausea I thought I might be pregnant (I had a tubal ligation 51/2 years ago) so I took a pregnancy test (came out neg.) But it's 3 days later and my left breast is still leaking. What could this be? I am very concerned. (I am a 27 year old female)