Congratulation for your bfp!!! What dose you took? My wife was told it has many benefits especially when you are TTC, if taken in appropriate dosage. As you said you were breastfeeding, vitex might have helped you in lowering high prolactin levels. Not only that, it increases production of LH, which in turn increases progesterone. Although there are no side effects, you need to ensure the herb you are taking is its pure form and of best quality for better results.
However, I read you need to wait for 6 months or so, to see its benefits. I must say, you are lucky to get it work so early!!! My tip for ladies, who are going to try this, would be to find a good natural health provider, who can advise on vitex use and dosage.