I would count the second withdrawal bleed as CD1 and count from there.

It is difficult to say when you may have ovulated as you don't mention any signs like EWCM occurring that could give us a clue. It would also depend on whether your cycles are regular or not, and whether you have been off the pill long enough for things to have returned to normal.

As for when to test - usually a good idea to wait until AF is late. Some tests claim they should work earlier, but I honestly believe it's better to wait.

BW