Some food for thought here:
To grieve doesn't necesarily requires you to cry. People grieve in diferent ways, and crying might just not be your way.

If you allow the pain to invade you all the way, and trully let it in, and then deal with it instead of avoiding it, however you deal with it (crying, or disconnecting from the world, or laughting) that is your way of grieving.

The important thing is that you allow yourself to hurt. It is ok.