The blood could be just about anything. Bleeding during pregnancy happens sometimes. It's just not a period because the uterus isn't shedding it's lining in preparation to rebuild. I assume that's what that was in reference of, anyway. I had bleeding in my last pregnancy and they couldn't really tell what it was from. Some bleeding is simply due to vessels in the cervix breaking.
Anyway.. when suspicious, test. Especially if this could possibly be your second missed period.
it should be lighter than a period, and much shorter with no clots or anything like that, and most people say it's a different color (either pink or brown) and more like a couple of random little spots. the blood is caused by the egg implanting and keep in mind that the egg is still small and won't cause that much blood as it attaches to the uterine lining.
Moreover, if it's bright red blood and you suspect a pregnancy, you should get checked out. Just because it's red doesn't necessarily mean that you're not pregnant. I had bright red bleeding 8 weeks into my pregnancy with no complications (at that point, anyway).