GagaJo, my condolences. What you are feeling and doing is absolutely normal.
We have become familiar with the classic stages of grief, but this part is not (usually) mentioned. You see it most clearly in children, and in this situation - you are a child.
I have no specific advice, but I personally find that knowing something is 'normal' helps me. You will still have those feelings, but you won't worry so much about them.
Of course it is possible that you have missed something, or have a memory of something that should be there and isn't, but I would not waste too much concern on that. Once you have cleared as well as you can, you have to let go.
Witzend - what a lovely expression 'your mother's precious presence'.
I hope the rest of the clearing goes well for you GagaJo, and that you find the clearing and sorting helps.