I am so sorry to learn of the loss of your mom. Truly and terribly sorry.
I, too, am an only-child. I envy people with siblings to share not only the burden of dealing with the "paperwork" of death but also the memories of my beloved father. There is a lot of work as an only-surviving child -- in the midst of overwhelming loss. I have handled my dear father's entire estate without any help -- while still being a mother and wife -- and there have been times I have certainly resented it. Grief is hard work and emotionally exhausting.
I have found that most people just don't get it. In a way, I am glad that they don't because it means that they haven't suffered the loss we have. I wouldn't wish that on my worst enemy.
I have learned to tell people what it is that I need from them and to say "no". When people spout useless platitudes I tell them that their words are unhelpful or hurtful. I let people know what they can do to help me. I also tell people that I am unable to do certain things presently. I don't know if that could help you -- but it has helped me.
Anyhow, whatever you do Sandra, I am sending you hugs via a stupid computer. I am sorry we share such a horrible loss.