is Vitex for irregular periods?

because um i have regular periods, i get one every month. And when i started Vitex, i would feel sick like throwing up , hot flashes , And i also was spotting on it? So that’s not normal? i would spot blood the day of when i was taking it or a ya after and i freaked out because my period wasn’t due for another week or 2. So i stopped taking it for the sake of my body . can anyone explain how it works? I mean i read everything and it didn’t say only for irregular cycle , it just said for trying to conceive a baby and that’s what i’m trying to do