H.F.
Call your doctor's office to let them know what is going on. It could be that he is getting some blood from your breast as well as the breast milk. If your nipples are cracked or bleeding, this could be a simple explanation for it. It is better, though, to call the doctor and let them know what is going on. They can let you know if it is something they need to check or if it is normal. My rule has always been, if I have a medical concern, call the doctor and speak to him/her or one of the doctor's nurses. Most of the time, they will tell you over the phone if it is something normal. If it is something that could be normal but could also be a cause for concern, they will usually have you come in to check it out. One of the great things about calling the doctor, though, is that it helps relieve a Mom's anxiety as well whether they say it is normal or that they want to see them. Either way we are doing something to take care of our kids. If it is a problem, it is being dealt with. If it is normal, then we don't have anything to worry about.
Good luck with little Noah.