No Spark

I've had the Bla's the last few days and I'm not sure why. I know the moon is full and the weather has been cold and rainy for several days, but I don't think that's it. I seem to go in cycles. There are times when ideas shoot out of me like static electricity and other times I feel as dull as lead.
When I checked my biorhythms they are all over the chart. So, I'm just going to have to ride this thing out until the spark returns.