I regularly chart my basal body temperature as a way of tracking ...

I regularly chart my basal body temperature as a way of tracking my menstrual cycles. Prior to starting Neurontin, my cycles were very regular, though I had an abnormally short luteal phase. I've been taking Neurontin for a month now: 300 mg 3 times daily. Now my basal body temps change drastically from day to day instead of following the regular rise and fall pattern of my cycle, and my period is 4 days late so far. Have any other women experienced similar side effects?