The fact that it's brown means that the blood is a little older, meaning that your period is about to end (because the blood flow is milder so the blood stays inside of your body longer). This is nothing to worry about and it's very common (a lot of my friends have it too and so do I - I'm 17 too) but to prevent leaking I would wear pads until the bleeding has fully stopped. It depends for everyone how long their periods last and its always hard to know when it stops, so wearing pads until you're sure that it has ended is probably the only way. Good luck! Xx
I have had the same thing. I wear panty liners on the discharge days. I don't think it is anything too concerning but if you are worried, talk to your doctor