Vitex????

So i have started vitex, this is my second month. Its good as last month i ovulated but now my period is still going and im on cycle day 8, before vitex my period lenght was 5 days but i dont think i ovulated for a few months. Had anyone else had longer periods and do you think it is worth while taking and prolonging my periods. Im on cycle day 8 but its only period when i wipe. Just need some advice please x