Implantation bleeding or af???

Honestly I think I'm just worrying myself over nothing, my period was only a day late, but now I've started (or so I think). My period has always been very heavy and the color has always been a bright red. This time around I'm only spotting, and it's all brown or extremely light red-close to pink. I have had unprotected sex recently so I'm not sure. I probably sound really silly/dumb, but I just feel really confused and I don't want to talk to anyone about it yet and worry them too. Am I just crazy?