Strange period.............. asap?

hi there my period are all ways like clockwork 15th of feb 2008 then agine on the 16th of dec 2008 i have a 31 day cycle i have had some signs of pregnacy on monday 5 days be for i was ment to be due on my period witch ment to start on the 15th of jan? but no period yet? the signs i had on monday was light tummy cramps on the left hand side of my uterus, head aches, and feelcking sick , and tired , tin taste in mouth, and all so on the 16th i had a lot of watery white dischage? and all so i think i had implataion it was only spoting it was to light pink dots in my nickers? and that only last for 1 day thro? and all so on the 7th of jan i done a pregnacy test come back neg? then i done a test agine on the 16th come back neg? all so to day this after noon i had very bad head aches and light tummy cramps down the bottom of my uterus and i had white water dischage agine the same stuff as i did on the 16th of jan?? hope you can helpe me many thanks xx