What Causes Delayed Periods After Falling And Having Sex?

Hi. I fell off of a horse a month ago, landed on my hip and suffered from a bruised hip bone, and some nerve damage. I have had unprotected sex since then, and took Plan B within 24 hours. But even before sex my period was late by two days. Now it is late by a week and a half. When I fell off the horse I also stopped taking my birth control. Could any of these effect my period? And should I still expect it soon?