So I have just received an e-mail from my professor saying that I didn't turn in the paper for Feb 22.

I have been very ill for a few weeks, so I haven't been able to make it to class recently, but have been getting the notes. I handed in the paper, and he is saying that I didn't. It's obvious that he thinks I am lying to him. What should I do? Has anyone else been in this position?

This is a full year course, worth 6 credit units, and also costs about $900.00! If I don't get credit for this paper, I will have a very low grade or even risk failing this course and not getting my credits!