I can somewhat relate to your post. Except I lost my brother almost three months ago. He took his own life and I haven't been myself since.
I wish I could say it get's better or that it will get easier, but then I would be a hypocrite. Not to mention everyone feels and responds differently so who am I to say such words.
It hurts to think of my brother, so I try to remember the good days with him as much as I can.
I am in no position to tell you what to do or suggest anything as it's extremely annoying to me right now, but I will say that I do hope you can find some way of smiling at least once in your day over the good memories of your son.