wife

So sorry for your loss. It is early days yet. Try not to isolate yourself from your family - but at the same time if you want to spend time alone and cry then do that too. All you can think about now is what you have lost but there will come a time when you will be able to look back and remember all the good times and smile. I found the hardest times were the "firsts", first birthday, first Christmas, first anniversary.

Give yourself permission and time to grieve, and think what your wife would want for you - I am sure she would want you to carry on and try to enjoy your life.

I'm so sorry, it must be really hard for you. It's bound to take a while for you to adjust and you're entitled to feel lost and sad - don't feel guilty about that.
I've not yet experienced this, but I know others who have. They've found that a routine helps. You don't have to do lots of housework etc. Set yourself simple, easily doable tasks that fit into your routine; make sure you spend some time doing things with your family and other people when you can; give yourself the occasional treat; see if you can find a social/leisure group that suits your interests or do an evening class. You may find these things hard to do at first, but give it a go.
My FiL, when my MiL died, insisted on cooking all his own meals, making pies and cakes (some were, ummm.... interesting) and not buying things in. It certainly gave him an interest.
It will probably start to get easier, especially once you get past all the anniversaries the first time. Keep putting one foot in front of the other, metaphorically speaking, and one day you'll look back and realise that you've coped. Good luck.