Could Taking Valium Cause Thick Discharge From Breast?

I am 24 year old female, 239lbs, high blood pressure and bipolar disorder. I breastfeed my daughter for the 1st 6 months of her life, but the milk would not dry up. After getting off Invega about 4 months ago my milk finally dried up. The last 2 weeks my breast have been sore achy and hurting, now I am having a thick discharge from my nipples that looks like milk but much thicker. What could it be? FYI I just started valium 5mg 2 days ago.