Ovulation Question with Picture.

Well, I'm confused. I finally got a positive opk 4 days ago and ever since then I've been having spotting. This is my first time using opk....so u need your help and advice please!!!! 
1dpo- light pink
2dpo- light pink
3pdo- brown
*that night I had sex and it was more of a red blood color after.
4dpo- picture below when I wipe 
Is this trend my AF? I've also had bad back aches throught the whole month. 
Is it possible to start your period this soon after ovulation. I ovulate on CD 23? I do get spotting before periods but they are usually brown, not pink/brown/ red. Please please what do you think?

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors