Vitex 1000micrograms - had a headache for a month but persisted. Had very strong O symptoms (CM, pains) but ovulated 3 days later than the previous cycle (17 days and pushed it out to 20 days!). Had very very painful spotting for 4 days prior to AF that was very strange. Apart from that no noticeable difference to my short LP.
Also on B6 but haven't noticed anything.
Wish I could lengthen my 8 day LP. Off to FS in 2 weeks they can help.