I can relate to what you're saying, Chai. My mom just died on May 27 after about 1-1/2 years of being bedridden due to end-stage Alzheimer's. I had been living with her and taking care of her since 1994, but never expected her to get Alzheimer's since no one in our family ever had it. I don't regret taking care of her at all, but the demands of caregiving got more and more intense until everything else was crowded out, even holding a job. It's impossible to maintain a good attendance record through repeated hospitalizations and constant medical crises.
I think not having a job to return to when your loved one dies makes it harder because there is no familiar routine or group of coworkers to give you any sense of normalcy. I'm sure many people end up in the same boat, especially with so many people dying from Alzheimer's and other long, drawn-out illnesses that make it impossible to work and caregive at the same time.
I did feel a sense of relief the day mom died, but almost instantly I was overwhelmed by the most horrible feeling of emptiness I have ever experienced. I felt utterly alone in the world. The house was deadly silent and all of a sudden ordinary objects took on a very painful quality. Things formerly associated with pleasant emotions suddenly acquired the ability to inflict intense pain every time I looked at them.
As far as my sense of self, I feel like a cloud of ether right now, just a formless, shapeless cloud of floating pain. Just wanted to let you know you are not alone in suffering from a loss of identity when a loved one dies.