Is this 2GA3 you're talking about?
I recognize your name from the 2IO3 tutorial.
I think what will happen is you'll just have to retake it later on. You could see if it's offered in the summer maybe? If not, then you can either attempt to overload next year or fourth year to get it done (assuming there's no 4th year course that requires it, not sure off the top of my head). Or if that doesn't work, you could take an extra semester after fourth year and finish it up then, and just graduate slightly later than planned.