Help!

I’m so confused right now. So I had a positive LH surge 4 days ago (Sunday) in the morning, had sex that night. The following morning OPK said negative so assumed I’d ovulated then. I had a bit of brown blood mixed with egg white cm 2 days after LH surge (Tuesday). Thought maybe it was from ovulating Sunday. Then today (Thursday) I get another positive LH surge in the morning later that day I get negative and a bit of pink blood mixed with egg white cm in the afternoon. What is going on? Is it too late to get pregnant if we have sex tonight?