When I had that trouble (I too got an online degree) I just redoubled my online posting and asked myself questions and answered them and tried to come up with related/helpful questions and comments and used the whole online "writing" experience to study. Grab questions from your textbook, ask and answer them online; make it your own site until someone complains or tells you not to.

If it happens all the time, I would find and transfer to another school where there is better feedback and interaction (my university, the University of Maryland University College, http://www.umuc.edu/ had pretty good interaction online, overall).