4 days of + OPK's but...

[BusyMomma]

I got a positive OPK 4 days ago. The second day looked about the same as the first but the third day was a lot darker and today (day 4) was a little bit lighter. I'm confused because I had cramping and back pain from O on day 2, so why is it still showing positive? Does an OPK still show positive when you have ovulated? I'm new to all this and not really understanding how OPK's work.

 

[NYcountrygirl]

got any pics, so we can see?