Peak opk but period pains

tara

I had a misscarriage about 4 weeks ago and have been tracking my ovulation so I know roughly when I due on my period as I have long cycles.

I had a peak opk 2 days ago, the day after we had sex, and now I have period pains but only mild.

Is it possible to get an Lh surge when due on period as I’m confused with the pains