I have been taking the same birth control for about 4 years now. My period is like clockwork, and I generally know when to expect it. When my period DOES come, it s almost ALWAYS heavy the first couple of days. So heavy, in fact, I normally have to wear a tampon as well as a pad. My issue is my period was a few days late, and isn t really my normal. I have been cramping really bad (normal), but also just have a little blood on a panty liner. That blood is very dark brown/black, and has been making me extremely curious and nervous. I have also been having a lot of joint pains and that never happens. What do you think could be wrong?