No, you are not going "crazy" or "losing it." You are grieving the death of special person you dearly love. Normal grief throws ones life into chaos, mentally, emotionally, physically and spiritually. Here are some normal reactions to grief & loss:
disorganization & confusion
changes in appetite
anxious, sad, apathy, fearful, teary, angry
lack of motivation
questioning existence, life & death
This is a time to be gentle with yourself. Take one step at a time and allow yourself to heal.