Yes, you should express your grief openly. By sharing your grief outside yourself, healing occurs. Ignoring your grief won't make it go away and talking about it can generally help to make you feel better.
Allow yourself to speak from your heart, not just your head. Doing so doesn't mean you are losing control, or going "crazy". It is a normal part of your grief journey. Find caring friends and relatives who will listen without judging.
Avoid people who are critical or who try to steal your grief from you. They may tell you, "keep your chin up" or "carry on" or "be happy." These comments may be well intended but you do not have to accept them.