When should i stop BC?

So in December my prescription for both control expired and I started a week later. I use it continuously without getting my period. Last month I tried to do the 3 weeks on and 1 week off but AF never came and I think it's because my normal cycle would have been a week earlier. Now that we are going to TTC, when should I stop using BC?

On June 3rd when my original schedule would have been or June 10 which would be the full 3 weeks? How will it affect ovulation?