For anyone whos had implantation bleeding?

The past couple months my cycle has been weird so im not sure when i ovulate or anything. I just have a general idea of when my period should come, etc. And we use the pull out method so its risky. We had sex during my estimated fertile week but he pulled out. I was due for my period today/tomorrow. Give or take a day or so. This morning i had light brown, light pink discharge. Barely noticable.. Only when i wiped, and lasted only a couple hours. No cramps. Its gone now. Normally id be bleeding heavily by now :/ does this sound like implantation or just a weird period?