I dont think the vitex will be an issue, as long as you stop as soon as you get the bfp. I had been on it too, but i found it made my cycles worse, so i had stopped for a bit anyway. My Naturopath at the time had said it would be fine anyway. I was the same with the estrogen (the vitex was increasing my progesterone even more so thats why i had to stop). If this month isnt your month try a bit of acupuncture too because i found that it was what really helped to regulate. (hopefully you dont need to though! )

The week that i could test i felt really happy/content. Then the week after the tiredness and other not so nice symptoms started.

So excited for you if its good sign!!!! I reckon if you work out 18 days past your o you should be able to test no worries!
Yeah natropath told me vitex is specifically for progest. She didnt prescribe it I wanted to give it ago before the herbs because of the difference in cost! Did you use herbs to get your estrogen up? I was thinking aobut accupuncture down the track also... Herbs first though I think. Natropath has been spot on with everything so far and been the only one to help with my health issues so I trust her compeltely