Breakthrough Bleeding/Spotting

I’ve been taking combination birth control for just over two weeks. For the last two days I’ve been spotting and I’ve had moderate cramping, sometimes really bad cramps. There isn’t an extreme amount of blood, but it’s enough to where I can use a regular tampon. The blood is bright red and brown in color. I’m probably just paranoid as this is my first time using hormonal birth control. Should I be worried? Or when should I start to worry about breakthrough bleeding? This is also around the time that I would naturally ovulate.