Every year, for the past several decades, this happens, and I always forget.
You see, my birth control pill comes in packs of 28. 21 days on, and 7 sugar pills I usually skip anyway. My doctor's appointments are annually, in August, and sure prescribes a new year at that time.
But every single year, about this time, I run out. Why? Because, if you've been following long with a calendar at home, you realize — it's because a month generally has 30-31 days, not 28 (except, well, of course February).
So every year, for the "month" of the prescription I fall 2-3 days short, which catches up in the summer. Right now, for some unknown reason, I have 21 days remaining in my prescription window actually, but they can't fill that because the pills come in 28 day cycles when you count the sugar pills.
But, according to my insurance (well, almost all insurances, really), I can't see my doctor more frequently than once a year.
The pharmacy will call my doctor, and she will issue a patch month, and it will be ok. But unless I am missing something really obvious (and I don't think I am, my doctor says she has to do this often), it seems like one of the stupidest, most easily remedied problems with the system. Aaaarrraaaagggghhhh!