Confusion

I’m a little confused. Af was here from March 21st through 25th. I have been taking the ovulation tests every day but nom of them have said positive, a few were close so I’m wondering if I ovulated those days. Anyways I noticed some spotting today, not a lot but enough to notice when I wipe. Is it possible it could be implantation? I’m on day 18 of my cycle. Af isn’t suppose to happen for two more weeks, I don’t feel any major cramping like I do right before af is suppose to show, just a tiny bit.