Hello, I'm A 46 Year Old Woman, And I Had

Hello, I'm a 46 year old woman, and I had my last child 13 years ago. I also had a partial hysterectomy about 3 years ago. Anyway, I don't do self breast exams regularly as I'm not sure what I'm feeling. I have lumpy breast tissue as it is. Anyway, yesterday I was checking my breasts out before showering and I have discharge coming out from only my left breast. It appears clear with maybe a tinge of yellow and at one point it had a tinge of blood. I haven't really paid attention to my bras to see if there's any spots indicating spontaneous discharge but it's definitely there when I squeeze it. I know no family history because I was adopted. What could this mean???