I am very sorry for your loss... If only I knew the right words to comfort you ;__; I can't imagine the pain you're going through, but I am aware that the grieving process takes time. It is normal to feel depressed when you lose someone close to you, so don't isolate yourself, over-analyze your emotions, and/or allow negative thoughts to seep into your mind. You are not useless. This is a difficult and complicated time for all members involved. Just be sure you're not avoiding your family because you feel bad (I often do this, and let me tell you: It accomplishes nothing!) As a family, you must lean on each other for support! I'm sure that's what your mom would want.