Learn to forgive yourself
It is easy to allow your sadness to take control for your feeling. I have found this piece of advice on line which some up how I feel.
Don’t be so hard on yourself regarding feelings, or thoughts pertaining to your loss. Your mind has to grasp the concept that someone you never imagined life without is now gone and that is your new reality. Your mind, your body, everything will counteract that reality. This is completely normal and apart of the process. Do not fight this, allow nature to take its course as you adjust to the new you, your new life; as you walk in your new shoes