Sounds like the brown period is probably old blood. When you have your period, do you flow very hard? I agree with Jun. You should be checked out by a GYN before you let it go too long. How long has it been going on already? Chances are, it is something simple, but you'll feel much better knowing the truth. The internet is full of helpful information, but it can also be pretty scary when you start trying to diagnose yourself. Don't let your mind go to crazy with it. Is this something you are comfortable sharing with your mom or another adult who could go with you? Please get it checked out. You'll feel so much better in the long run.
Gail
what is exactly brown period mean? Symptom(pain) you are having can also be caused by ovarian cyst. I would suggest that you go to see a GYN dr if your pain persist more than 2 weeks, have a trans viginal ultrasound to begin with. Best wish
Peace
Jun