have a headache

I should be ovulating right about.....now.  Then again, peeing on a stick hasn't indicated that it is so.  (hee hee, sob sob, hee hee - cry or laugh? not sure which I want to do)
So the question becomes: is my headache caused by the endo?  Ovulation? rain? allergies? something else? all of the above?
 
Grrrr...I wish I tracked my small annoyances more closely before.  Today's headache is annoying, but not debilitating.  That's the way it usually is.  I feel like crap and don't really want to do anything work related...but can hold a conversation and type on this site.
Am I a whimp?  According to the doc, I am "one tough cookie."  She was shocked to see how much pain I could endure through the ectopic pregnancy.  So, the fact that I don't feel like working right now is a-ok.  I need to listen to my body, give myself a break, and thank my lucky stars that my office is so accomodating.