Hey ladies I just need some advice,

I finished my period about 1 week ago. Yesterday I had what felt like period cramps but only in my back. Today, I have a small amount of brown/reddish blood. Wondering what this could be? I’ve had sex twice since finishing my period but we used a condom. There would be no way I’m pregnant. Glow says I’m on my fertile week but not ovulating yet. Any advice/insight would be greatly appreciated as I am concerned and not sure what to do or what to really think