I give in and do a hpt only to get AF cramps or AF herself within a few hours later

This has happened to me sooo many times since first starting to TTC!!
Since having DS i get Af cramps up to a week before af is due they stop 1-2 days before and the af arrives.

Af was due today, i have had no cramping, nothing....so i was going to test in the morning but gave in a few hours ago, it was bfn, and now, you guessed it i have af cramps!!

Last time this happened (ttc #1) i had no symptoms tested, bfn, 2hrs later Af showed up!

I really find this frustrating.