You have my sincerest & deepest sympathies. Losing a parent is difficult enough when one knows its coming. To have it some seemingly out of nowhere as it did to your mom is a shock and trauma of a scale which I cannot pretend to even imagine.
From your account, your mother and you had a great relationship with no heavy duty "unfinished business". For that, you can, and hopefully will, be grateful, eventually, once you have time to sort all this out (and I'm sure Rob can tell you that it probably will take a while to do that). Also, it sounds as if your mom was one heckuva woman, a person of outstanding character and resiliency. For that, you can forever be grateful.
Life does indeed go on, but not without deeply painful surprises. Stay strong and draw inspiration on your mother's survival instincts. She no doubt passed them on to you.
Again, my deepest condolences to you and yours. By all means, continue to post here as the need and/or desire arises.