Rockstar, I really don't want to be patronising but I think you need to be a little patient, it takes a while for something like Vitex to work because it's not a drug its a herb, therefore it's naturally trying to correct a problem (if it can) your body is probably desperately trying to ovulate but it's probably still growing your follicles. At least give it a few weeks, if you start pumping it will all sorts of things then you might find it just makes things worse.
I am hoping it does something for me, I'm cd17 with no ovulation as of yet but I'm staying optimistic, my last cycle was long and came naturally without vitex so I will see if the 800mg daily makes it shorter this time round.