Pregnant With Pus Like Discharge From The Breast. What Is It?

I am 38 weeks pregnant with my third child, both my first two were breast fed. The one glad on my left areola has always occasionally had a small amount of white discharge but nothing major or alarming, and from what I understand this is normal. However, today that same gland seemed to be swollen and the vein beneath the skin on it seemed to be swollen as well so I applied a bit of pressure and instead of the slight little dot of discharge there was a large amount of discharge, still white in color but with a pus-like smell to it. I squeezed again and more of this discharge came and now the gland is hard and bump-like but the pus like discharge is now more clear with a bit of a pink like tinge to the clear liquid. I am wondering if perhaps this might be mastitis however as I have not yet given birth am unsure and would like to know what this might be/what I should do and whether or not this might jeopardize my ability to nurse my third child once he/she arrives?