Question. I'm 3 days late and I'm never late!

My husband and I are trying to get pregnant! We've been trying for 4 months now and I have a exact 28 day cycle I'm now 3 days late and he wanted me to take a pregnancy test. It came back negative but I have this thick white milky discharge and no symptoms of cramps or anything like I usually have 3 days before I start my period. Could I be pregnant? Why is it coming up negative if I'm late? Is it to early to tell? Please help.