Bleeding because of pills?

I asked here 14 days ago whether I should see a gynecologist because I had bled three times within a month.

Now I went to my gynecologist on Wednesday and she prescribed me Agnusfemina, but the pharmacist gave me Agnucaston because she said it had better ingredients.

My doctor didn't find anything unusual during the ultrasound, so she prescribed the herbal supplement. She also said it would take a while before I got my period again.

Yesterday I had some spotting and today it's actually like my normal period, so could it be because of these tablets or is something wrong because the gap to my last period is 16 days, just like the gap between the previous bleeding.