I am so sorry about your loss. But I believe your brain is trying to use your coping mechanism right now.
I did the same when my grandmother passed, she lived with me. I won't go into details, but my brain did this and I was going crazy with the guilt of not crying or the sadness I should have been feeling. But I had a lot of things I had to accomplish with arrangements and the such.
After awhile, you will balance out then you will be able to start the grieving process.
wishing you peace