How to ask a professor for help... again

This is my first time using this and I'm just looking for some advice. I'm a 6th year senior in college and I'm and working through hell and high water to actually graduate this year. But I "fell off the wagon" and now I'm really screwed. I missed classes and then we had school break, and I look at the syllabus this morning to realize that our midterm for one of our classes is today. OH NO! It's acutally started now. I don't want to drop the class but I don't know how on earth to begin. I can't drop the class because I'm on academic probation (we're not allowed to drop classes, and I'm only .1 away from my GPA being in good standing) Basically, what do I email the professor? Or say to her when I visit her inn office hours? How on earth do I ask to retake the midterm once I've studied for it. How the hell do I save this class?

You must have KNOWN what you were risking when you 'fell', surely? Unless there were extenuating circumstances that justify your having fallen off the wagon and qualify you for a re-take that you can present to your professor, I'm not sure how you do save this class, is my honest answer. So - were there?