Clear blue advanced OPK question

Any ladies out there using it? I went more advanced this month since I've had trouble getting a pos opk reading. This one measures estrogen levels too. So here's my quandry: I've had "high" fertility readings for 3 days now, and thought that for sure I'd have a  "peak" reading by today. Any body have a long "high" reading like this? I'm still BDind once a day for what glow calls my fertile period, but I'm so curious about what's going on. Thanks!