Please help me understand OPK

So I am currently 8dpo and my period is set to arrive on the 4th. I am so anxious and impatient that I decided to just go and take both a Dollar Tree hpt and opk today. Obviously the hpt (pink test) is negative, but the opk test (purple test) has a faint line, what would this mean so close to my period when ovulation has already occurred? Sorry if this is a dumb question, I just have no prior experience with OPKs