Positive OPK 5dpo

I received a positive opk on CD18. Negatives afterward- I like to monitor the decline. For shiggles, I took a opk yesterday at an assumed 4dpo and it was positive. Took a second and used the strip analyzer- it was positive too. Took 1 today and it was positive. Took a First Response opk & it was barely negative. Two hours later Strip opk was positive (used analyzer as well). My cycles range from 27-40 days but on average are 29 days or so. Took Vitex 1st two weeks of month.

BD every day from CD 13 to CD 22.

What do you guys think? Is this a second LH surge? Or late ovulation?

Thanks!