Hmmm....if that is the case then I have been either ovulating or pregnant for my entire cycle! I have literally NOT had an OPK without a second line on it ranging from very light but still completely obvious in all lights at arms' length to the kind of second line you'd be happy to see on a HPT. And I'm patently NOT pregnant and at 6dpo as I am now, I'd be incredibly surprised if my gradually darkening OPKs were anything other than the fact that you have LH in your system at all stages of your cycle.

Peeonastick.com has some interesting things to say about this.

Lisa