Implantation Bleeding?!

Can anyone tell me what implantation Bleeding actually looks like?? Especially for a first time pregnancy? I keep trying to Google and the results are all over the place. My period isn't for another 12 days and my hubby and I had unprotected sex about 8 days ago, a day before my predicted fertile window. I know that it typically occurs 6 to 10 days after ovulation but it's possible that I ovulated early so everything is totally up in the air right now and it's stressing me out because I definitely do want a baby but idk if I'm normal or if I should be worried which ultimately makes me worried. And I've literally never had a period come 12 days early in the 11+ years I have had one. I also read it could be stress but I don't feel like I've had more stress than usual, that was last month and the month before and I was still fairly regular. Halp plz! :'(