Well done, Grumpy. I try to fast forward my thinking to better times. Do you have something to look forward to that you can focus on? A holiday, perhaps? I would try to ignore the present and just go forward in time in my thoughts. You are stronger than you think. You can do this and come back to your normal life. The first thing in the morning is the worst and then it gets better as you move into activity. I should say that is how it is for me anyway. Stay strong. We have a saying, Fake it 'til you make it.
After all this positive stuff, should add, give yourself permission to grieve as well as it is natural and necessary.
Best wishes