Colostrum discharge.

I have been married 5 months. Being on birth control for about 7 months. I have thought a few times I was pregnant but I always get a period. My breast are a 34 j and I constantly have pain from them. Both myself and my husband have noticed, a yellow discharge from my left breast. I went to the doctor back in February. She said it was nothing. But now it's slowly becoming more and more. Am I reaction to the birth control or am I pregnant and don't know it because the birth control has changed my hormones?