Hi Nikki 39,
what cd did you start testing and what time of day? Is there any chance you could have missed the surge? It can be quite confusing. I would keep testing and see what happens over the rest of the month, it is sometimes worth doing an expensive smiley face opk when you are uncertain and first starting out with OPKs as some of them are a bit rubbish... my ones only get dark enough on the left of the marker when I ovulate so was really confused when I first started out.