Oh my God! I thought I was the only one! Thanks for bringing this up! It took me a while to realize that most of my attacks come around the "you know what" time. ;) I went to the ER a several months ago and the nurses alerted me to this - he also said that MEN have certain cycles as well that may affect anxiety levels (I had inquired "OK, that explains me, but what about my dad, who also has anxiety?")
What I try to do beforehand is make sure I'm exercising (yoga, walking, whatever), cut back on salt intake to reduce bloating (that's right, I said bloating!), most definitely stay away from caffeine, and remember, as they say, this too, shall pass. At least till next month!
Hope this helps! And thanks again for broaching a sensitive subject!!! :)