So sorry to hear this Gil .... Mothers are quite simply irreplaceable in our lives!
You were lucky to have her for so long I would say, as I lost mine more than 20 years ago, and my Dad 44 years ago now, but they both still get thought about daily and they both still hurt, even after all this time.
Just remember, what you feel whenever you think about her, will be a permanent reminder of the life she gave you and that you are in fact still alive yourself!
May She Now Rest in Eternal Peace