I lost my dad to a sudden death a few years ago, so I feel for you. My prayers and condolences to you, OP.

Some people have already posted many good points on here, so really many of your bases are covered. But I can't stress enough that you should look out for your own health and EAT something.

Eating I cannot stress enough. I was so overcome with grief over my dad's sudden passing that I barely ate anything for almost four or five days straight due to having no appetite whatsoever. Not only is this unhealthy, but it'll also sap whatever energy you have left over from the emotional toll that has taken over your body. You and your family are going to be busy making both burial and legal preparations concerning your mom's estate, so you need to at least keep some of your strength up.

Lean on your family during this time. They are there to help you. And if you need time to yourself, don't forget to take it. As somebody else told me (he lost his father right before he had to take his medical board exams), take some time to get your head around you whenever you need it. You have a lot to do, but also remember that you're only human. If you need to take a walk or take a breather, do it. As he put it, "If there's ever a time to be selfish and take whatever time you need to get yourself back together despite all the preparation, the legal issues, and the paperwork, the time is now. People will understand because you are going through a sudden, traumatic loss."

Again, I am so, so sorry for your loss OP. The death of a parent I would never wish on anyone. I will not lie to you, you will be feeling as if part of your heart is missing for the rest of your life. It's been almost six years for me and I still feel that part of my life had been ripped out and stomped on mercilessly. But remember, things will get better and all the paperwork, finances, and the work that comes with the death of a loved one will settle down within the next couple of years.