Spotting

becca
Okay please someone reply. 
I had my period the 8th aug and I had protected sex on the 13th and the 15th (used a xondom) to our knowledge the condoms didn't break and we checked. But since Thursday I've been having light brown discharge on and off plus today I had discharge a bright red line. 
Is this implantation bleeding? 
I've also been experiencing nausea and mild cramping but I don't know if it's ovulation or just the face I'm really anxious.