Positive OPK 1 day before period due

[Moomoo20]

Hello, so my period is due tomorrow/friday. I'm currently 12DPO and have been ttc for 7 months. I had sharp stabbing pains near my right ovary at 9dpo and I thought oh this could be implantation. I have no access to pregnancy tests for another 2 days, so I decided to do an opk today and it's very dark and positive (confirmed in app). I had a tiny bit blood tinged cm this morning, I feel like it's too late for implantation blood as my period is due tomorrow/friday. The positive opk has thrown me off though. I read opks can pick up hcg too if you are pregnant. Has anyone experienced similar?

They absolutely can pick up HCG.

They do pick up HCG. I kept getting positive opks after my MC even though the pregnancy test was faint. I did an opk to see how dark it would be when I got a BFP again and it was dark. Definitely get pregnancy tests!

Thanks ladies, I had really sharp pains in my left ovary for about 30 mins and now just all over cramps/back ache, I usually get this just before AF :( but I'm still keeping everything crossed!