I am sorry for your loss. You have certainly suffered more then any one person should ever have to. There is no easy way to cope with this kind of loss which will feel like the right way. I do need to ask how long ago it was that your wife passed? This will give me a better understanding of your situation.
The loss of a loved one is the greatest grief anyone will ever know, and from what I understand from your post, you also suffered the loss of a child as well, is this right? If so the pain and hurt you are dealing with are greater because you not only lost one person but both. You are probably filled with mixed emotions and not really sure how to cope or deal with any of it. The sudden passing of a loved one always tends to hit us hardest because unlike when we know that someone has been ill for awhile and we have time to somewhat prepare ourselves for their end, when we lose someone suddenly, we haven't been given time to understand, cope with or process what has happened.
If this was a recent loss then you are still in the grieving stage and this is all you know how to do. You have become dependent on your wife, used to having her around and the shell shock of her no longer being around is still all that consumes you. Unfortunatly at this stage, people may try to offer you advice and help, but, this often falls on deaf ears because you are grieving for your loss and this is a personal process, something you and only you will know how to do for you.
If your loss was awhile ago then you are more then likely in what I like to call the "Loss of living" stage. This means that you have went through the basic steps of grieving and upset over your loss and have settled on the fact that without this woman your life has lost all meaning and you have probably given up on any kind of life you had before. You find yourself just going through the motions everyday. Go to work so you can pay your bills, but, you are still falling behind in your bills, come home and thats about it. You may find yourself avoiding friends and family and general outings, making up excuses or finding reasons not to go out. You have found that the only place you want to be is in the home that you shared with your wife. Again, this is a process that only you can go through and although you may take friends and family along for the journey with you, you and only you can determine when you will be able to cope enough to move on through this stage.
I do feel the need to ask for more information though to better understand your situation so I can offer you help if you would take it, but, for me to offer you my best advice and help, I feel the need to better understand your situation first. When did your wife pass? Did the child pass as well? Do you still live in the house that you shared with your wife? How far along was your wife when she passed? Do you still have pictures of your wife up and does your house look the same way that it did when she was alive?
I understand that these are intensly personal questions and I mean no harm nor do I wish to cause you more pain, I simply wish to better understand your situation so that I may, even in some small way help you with your loss. I am here and ready and willing to help you in any way that I can. As soon as you are ready to recieve that help. You and only you will know when you are ready to reach out for help.