Sorry for your loss.

I used vitex to shorten and regulate my cycle when I was TTC Caleb as it was all over the place.

I researched it and decided that as it wasn't recommended during PG that I would only take it up until I knew I had ovulated.
Not sure if that helps you as you didn't say if you took it the whole cycle or just part of it.

I also read that once your cycle becomes regulated you can reduce the dose. I didn't get a chance to try that as it only took a few cycles taking vitex to conceive. It did shorten my cycle to 27 days for the last 3 before Caleb was conceived.