I am so sorry for your loss. You have gone through hell, and there are no words. PLEASE keep in touch with family, lean on friends when you need them. I just went through the same, Dad a while ago, My Mom and Sister within 3 month of each other last december, and while this is not much help, things do get easier as time clicks by.
Again, I am very sorry for your loss, my sincerest condolences to you and your family.
Thoughts and prayers.