When I lost my daughter, I was given some very good advice. I don't know if it will help you, but I hope so.
First, you can't recover straight away, and you shouldn't try. You will be happy again, but it will take time and improvements will be in small steps rather than giant leaps. If you can, stop trying, and let the healing come little-by-little. Focus on smaller, achievable things.
Set yourself small goals. Make a plan for the next day, in the simplest way possible. I had things like get dressed, leave the house once, make meal for kids and wash my hair. Every time I managed to tick off my list, I felt a tiny sense of achievement, which was better than the hopelessness and despair, and as time went on I added more things. I started a routine of going for short walks with my kids every day. I find it hard to feel miserable while I'm walking, even if it doesn't make me actively happy.
Is there a small thing which can be tricky, but you have the knack of? For me, it was making fruit cakes without the fruit sinking. I took the extra cakes (I made a LOT of cakes!) to neighbours and that gave me a safe, easy way to have some sort of social contact. I also went to church even when i couldn't pray, because I was surrounded by people without having to talk much to any of them.
Lastly, please try not to be too hard on yourself. After the terrible loss of your daughter, it sounds like you came to rely on your marriage for safety, stability and comfort., and now you are losing that. It probably feels like another bereavement, and that's totall understandable.
There is hope and I hope you find a way through. It took me at least 2 years before I felt anything like my normal self again, and I'm still inclined to isolate myself when I'm under stress,but life is so much better now. Keep posting here, I found it easier to type than talk, and it allowed me to get things off my chest without dumping all my emotional load on my family.