Angry Day

Today was not a good day. It was nice I still have a job after speaking to HR. Afterwards, I felt angry about everything. I feel like I should have been one of the lucky families that mom survivor cancer. I felt like mom should have stayed to help me take care of granny. I felt angry at a innocent granny for being here instead of my mom. Why am I having these emotions. I even was mad and angry at the therapist. I just be angry all today. Does anyone have any suggestions on how to handle anger or overcome it?