Thanks for trying to show me how to get it myself. I tried drawing it out, and I definitely ran it through my mind several times, but I didn't think we would have to check the tail in "before". I tried to instead to check the head for a null pointer, as in "after".
The assignment is due today, so I am submitting it now, but I am also going to look over it closely so I can understand how I should be "thinking" about linked lists for next time.
Once again, thanks for all your help, and I hope other students benefit from this post as well!