Both my parents and my MIL passed away just last year. It doesn't matter how old you are or they are, the loss is the same.

The only thing you can really do is slowly learn to live your life one day at a time despite a parent's abscense. Your mother would want you to carry on and work on having a happy life, that's what loving mother's really want for their child. What a child loves a mother and really misses her, then the mother has done her job well. Please focus on all the memories of her caring and kindness, that keeps her always with you.