Though it may not be clear at this moment, there is a logical explanation for the change in your behavior. I would encourage you to think deeply about what that explanation might have been. Did you start a new job? Did you recently move? Was there a recent death in your family? Something has to account for the change in your behavior. If it wasn’t an event, then illicit drug use is another possible explanation. You did not mention drug use but without many details I can only speculate. A significant behavioral or personality change might be indicative of an organic brain disorder but that occurs only on very rare occasions.
With regard to your focus of your family dying, that is a sign of anxiety. Some individuals with a particular type of anxiety disorder (obsessive-compulsive disorder) focus their anxiety on a potential future loss. The anxiety associated with that potential loss creates a great deal of fear. Individuals who are anxious and fearful can feel upset and potentially angry over the loss of control associated with that which they fear. Again, it is difficult to know what may be wrong without knowing more about your symptoms and your personal history.
I don’t necessarily think that you need a “brain scan” but it would be advantageous to meet with a mental health professional. A therapist could delve deeper into your issues and analyze what may have led to your recent change in behavior. Generally speaking, there is a logical explanation for why you are fearful, angry and unable to control your anger. Something is causing you to feel angry even if the reason is not self-evident. The advantage of seeing a therapist is that he or she can provide an objective assessment of your situation and can perhaps identify life patterns and trends that you may be overlooking. I hope that you will consider seeing a therapist. Please take care.