What are the effects of taking a premenopausal combination of herbs?

Are there any side effects such as extreme tiredness & lethargy that would be caused by taking an herbal combination of black cohosh extract, dong quai, licorice and vitex extract??? I was told by a dr. I could take something for perimenopausal symptoms. Could this cause such tiredness that you'd just HAVE to lay down or fall down?? I was so extremely tired ALL the time and having trouble staying awake. Comments that are helpful would be appreciated. I thought I was maybe taking something that would help me but maybe not, huh? Please answer soon. thanks and God bless you all for helping me.