It's O.K. to think strange thoughts and be really angry at death. Let these emotions come out through releasing techniques, find times and places to release this anger or turn this energy into a positive action. I just want to quit. I don't care anymore. I can't feel, respond, or think.
Depression is a normal part of grieving.
When you grieve you tend to pull your feelings and emotions inside and withdraw from everyone, sometimes including family and friends. You are sometimes quieter, lethargic, you don't eat or sleep well, or you cry a lot. If this were a human family member that passed away, your friends would bring food to the house, sit quietly with you and let you get over the shock. BUT If it is a pet, your friends are likely to invite you to dinner or a lively party or buy you a replacement pet. Very Bad Ideas, but they were meant as good intentions.