Periods probs

Kennedy
Okay, so I started my first period about a year and a half almost two years ago. Sometimes I get two periods, one that feels like an actual period and then one just bleeding. Last week I had brown discharge with a little bit of blood. What does this mean? Is my body trying to figure it's self out? Should I be worried? It usually happens like two or three weeks after my period... Or doesn't happen at all! Thanks!!