Mine come randomly too, but like I said, once every other month or so I can deal with. I just have to be careful and make sure that if I am somewhere and feel one coming I get home FAST before I can't drive.
I did notice a decrease when I came of the BC as well. And there are days that if I go without a soft drink (caffeine) I start getting one around 3 or 4 in the afternoon, but it is VERY rare that I don't start my day with a Diet Pepsi. (Funny, they claim caffeine and chocolate contribute to them.
)
I am definately going to try the Red Bull trick next time.
I've heard that Icebreakers gum will stop one. There is some ingredient in it--and I SWEAR I knew what it was and looked it up once--that will lessen them. My mom swears by it, but it didn't work for me.