Ovulation test questions?

So i have a question. I’ve been taking clearblue advanced ovulation tests everyday, once it showed high i started testing twice a day so i didn’t miss my peak ovulation. Why would i have two days of high and then all of a sudden low? Could it be bc i tested and my pee was to diluted or something? Going to test again in the morning to see what’s going on, just wanted to see if this has happened to anyone else? This is our 4th month of TTC since getting off of birth control and this is the first month my tests had started to look semi-promising.