OPK Pregmate Ovulation Strips - help!

Has anyone been using the pregmate ovulation strips? This is my first month using them and they are confusing. The instructions say to read within 5 minutes. I took one today and after 5 mins it was negative. However 2 hours later I looked at it and it’s positive. I want to make sure I didn’t missing something so I took another test 2 hours later and waited the five minutes. That one is negative. Can’t tell yet if it will dry the same because it’s recent. Any help with this brand would be so appreciated.