Loss effects us all differently, my advice is to let yourself process at your own speed. If 'staying strong' is important to you then do so, however make sure you're not doing it to mask how you're actually feeling, do your family really need you to be strong or your self? Putting extra weight and responsibility on yourself when you're probably still in shock might not be wise. That said if you act strong perhaps you'll feel stronger, though if just masking then you might be missing out on chance for others to see your pain and help.
I lost my Mum over 10 years ago and still miss her dearly, I found it took a very long time to find 'safe ground' again and re-order the universe and any extra stresses and responsibilities you take upon yourself might weigh you down even further.
Remember all the things you loved about her (I know is painful) however that is more important than the pain, the pain eventually subsides however the loved things remain so focus on them now perhaps and treasure and share them, it's okay to laugh as well as cry, your family will be going through very similar emotions and if everyone is pretending to be strong you might miss out on the emotional connections to see you all through. I might be totally off base though hope the 2 cents has helped in anyway.