What is this? TMI. Please answer.

Is this pregnancy CM or what? I've had it before but only when I've been pregnant. I was due on the 12th of June but I started spotting on the 31st of May. I spotted for 2 days, red blood, and then it disappeared. There were no clots or anything in it. Could that have been implantation bleeding? What's the deal? Me and my SO aren't trying but also not preventing.