Certain programs year after year have trouble filling. You might want to check the results from previous years to discern a pattern. Although this is no guarantee, it sometimes can be helpful. Also, although the most important source of information, the Match Unmatched List is not the "be all and end all" of open positions. Sometimes sending out blind applications to programs you think might be interested in you is a possible way of getting a position.
Know, too, that there is a "second wave" in the Scramble. Some people, for whatever reason, do not show up/or finalize their contracts at their matched programs and thus generate a certain number of spots in late May, early June, and even early July.
Just some things to consider. I hope this is of some help to you.
Nu