Three weeks now i've felt i've had a head injury at first i thought i was poisoned then i was sure i had a cervical artery tear i went to the er they didn't diagnose now i have depressive thought no focus i don't understand the concept of human being?

Unexplained symptoms: It must be difficult, having thoughts that you have been poisoned, had arterial injuries or a head injury as well as losing focus & experiencing depressed mood.. It sounds like you are puzzled. Have you considered seeing a psychologist or psychiatrist to try to make sense of it? A comprehensive evaluation may shed light on your condition. Take care.

Need to examine: It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Wish you good health!