As you already know your lack of shadowing hurt your application. Another factor is the small number of schools you applied to. It is worth reapplying to the schools you applied to before (except Northwestern) and consider adding these:
Quinnipiac
Boston University
Vermont
Hofstra
Albany
New York Medical College
Penn State
Drexel
Temple
Jefferson
GW
Georgetown
Wake Forest
EVMS
Oakland Beaumont
Western Michigan
Rosalind Franklin
Tulane
Miami
Roseman (new school accepting applicants at some time in the next year)