I am 13 dpo and 2 days late for AF. I took vitex over the past month as I believed my luteal phase was too short and my progesterone was out of whack (lots of imbalance symptoms).

Right now I feel nauseous and foggy and don't know what's going on...I've done 2 tests (yesterday and today) and it's BFN

Does anyone have a clue what's happening? Usually I wouldn't dare to think I'm pregnant (I'm 38 and been TTC for months) but there's something up. Or Did Vitex increase my cycle length in 1 month?