Breakthrough Bleeding

Okay so I've been taking the same birth control for the last three years or so, and before this cycle (I will start my period in five days more or less), I've never really spotted before a period. But for two days now I've had cramps (probably a five or six on a scale of 1-10), and I've had semi-frequent spotting. It's a light brown color. I've read online that it may be due to the fact that I've been taking it for so long that in a sense I've become immune to it, so I might need something stronger. And I've shown other symptoms too regarding changing medicines, but I guess with all the other stresses in my life I've been feeling extra worried about it. Has this happened to anyone else? Any advice? :(