So no one has responded at all. It's now June, have you gotten your period twice by now? June is the month you'd be skipping, correct?
I'm actually very similar to you. Before I was on the BC pill I was every other month. I was on the pill for 11 months and my period became extremely regular. I have been off the bc pill for a couple of months and my period has been doing wacky things. After getting off the pill my period came normally. Then it came 46 days later, then 11 days, and now it's been 49. I'm probably reverting back to before I was on the pill. Which means the next period I get is in July at some point.
I don't know the reason for this, I'm under the impression that it's either hormonal problems (which is why I got off of hormonal birth control) or that some women are just regular in this every-other-month way. I just want you to know that I share this same routine and am also looking for answers.