Wappy cycles, short lps, nothing is working! Vitex- when and how much to take??

[live_in_hope]

hi ladies! I am beyond gutted that nothing is working....i used to have normal cycles but since nov, everythign just went crazy

Been on a vitb complex for about 3months, but it hasnt extended my lp at all (cd1 today after an 8day lp)... I think i need to give chasteberry a try.. What dosage do i need and when shall i start taking it? Thank you in advance xxxx