So sorry, Di.
It does feel like that for a while. It's a huge shock when you lose anyone so close, especially so unexpectedly and so quickly. I know I questioned whether there was any point in going on after my mum died. I felt I had lost my purpose in life and it was hard to find anything to live for again, but slowly you do find ways to move forward.
I think loss is so final and so painful that it just floors you for a long while and makes everything seem pointless. But in time, you can find things that help you move forward. I found it helped to look at practical problems first and write down a plan to deal with those, which almost two years on, I am still following and that makes me feel I still have some control over my life, which at the time my mum died, I felt I lost for a long while. Then I began thinking about what I could do to help myself feel better and it was just little things at first, keeping a journal of how I was feeling each day and what I was thinking about. It helped alleviate the guilt and pain to write it down. It helped get it out of my system and I did feel better after doing that.
Like you, I left to come home for a rest the day my mum died. I had stayed with her all night for four nights in a row, so that she wouldn't be alone, but she died within two hours of my leaving, so like you, I felt terribly guilty for going and it still upsets me now, but you run out of energy and get exhausted and in my case, that happened at just the wrong time. In your case, it sounds like the doctors got it wrong and you were expecting to have more time than you thought to spend with Dave before he passed away. You mustn't blame yourself for that, Di. Things just happen as they do. We all try our best to do what we can in those last days, but events are unpredictable and things we don't expect do happen. We do our best with the knowledge we have at the time. Things just don't always work out the way we would have liked.
Although, I am told that sometimes our loved ones seem to wait for us to leave as they don't want to go while we are there. Perhaps that would be too painful for them, but I am told it is a common occurrence, for whatever reason. So perhaps that was your husband's choice. Perhaps it was my mum's, but like you, I wish I had been there and always will.
I also put flowers around the house as it lifted my spirits a little to see their beauty and smell their scent. Walking in the park also helped. It was a calm and lovely place to sit and try to process all that had happened and still helps now.
I think you do have to employ lots of little such strategies in the early days, just to help you get through the day. You won't feel like it, but you must also try to eat and drink enough, as you will only feel worse if you don't take care of yourself.
One day at a time, Di. Slowly the light comes back into your life and this phase of not being able to see any point in going on passes, but it will take small such efforts on your part to help yourself a bit. Tiny steps, every day until it starts to get better. Sending you a warm hug. xx