Why can't I cry?

Lately I’ve been sad….Listening to songs that just make my heart feel like it’s weeping…I feel my emotions about to spill on the floor but I just can’t seem to get myself to cry….I don’t have a tendency to cry… I just been feeling like it, but I just can’t seem to get it out of my system…Is this a bad thing? Am I a wimp for wanting to cry?