Wow, I am SO sorry to hear that. There's nothing I can say to make you feel better, but I can at least offer some advice. Find some friends or family members to talk about her with. Tell stories about what she liked, what kind of weird but funny things she would do, stuff that she would say, things that were "so mom".
Know that while she may be physically gone, the lives she's directly touched will live on for decades. And even if no one knows her name after a thousand years, the difference she's made in the world through the lives she's indirectly touched--such as ours, and the lives we touch--will last forever. No one ever really dies. Like indelible fingerprints on a clay pot, everyone has a legacy that molds the future.