Maybe that's it. There have been some other stressful things going on as well, including some (good) very high stress work things that required long days and came off very well for me a week after my mother's death, and probably inspired the back-stabbers. I only took two days of bereavement time, though I could probably take more if I asked to do so.
W2R,
First, I am sorry for the loss of your mother.
On employment, I can only add to what others have said. You have a lot going on and need to take care of your self first. Take more time to grieve, using either SL or AL, depending on what your supervisor will allow. You obviously have shown that you are a valuable employee. Paid and leave without pay may both be in order. You should be able to take time and recover without jeopardizing the long term value of health care.