Could it be?

I don’t know when I ovulated this month. According to glow it’s today, but according to the opk strips I just got it’s very negative. This afternoon I experienced cramps that were moderate. It stopped after a little bit. My period isn’t due for a while. I had sex on the 24th and again over the weekend thinking I was ovulating. Could the time on the 24 be implanting? That was about 9 days ago. Still having a negative test. I’m also experiencing a dull headache. Just upset I’m so mixed up with glow and the strips. If af shows up this month, when do I start tracking ovulation using strips? I need to figure out my cycle.