The first anniversary is always going to be a tough one. Are you reliving everything that happened this time last year ? A year isn't really very long to grieve so I think it's perfectly understandable. This will get better but grief goes through it's own process. I am sorry you are so sad but I can only say that eventually things will improve for you .
I'm so sorry to hear of your loss and your sons. I often find I cope on anniversary days as I prepare myself to cope and then when you least expect it the wind gets knocked fair out of your sails. You will find as time passes you will have these moments/days. I'm not sure there is much you can do other than let the emotions flow whatever they are. I think it helps to let the emotions out rather than bottling them up, I guess most people feel the same. If you find you are experiencing one emotion more than others then think about putting in place some ways to work through it that works for you. A simple example may be with anger taking a boxing class. I don't think that would work for me so please know it is just a simple example. Take care of yourself too. You are as important as your DS.