You discussed having previously been in therapy and my impression is that you are currently not in therapy. If so, then consider returning to counseling, perhaps this time with a different therapist. It is important that your symptoms are monitored.
To answer your question directly, the presence that you feel is not your brain attempting to protect you from your obsessions. It may be a hallucination. A person experiences a hallucination when they sense things that they believe are real but are in fact not real. Examples of hallucinations include hearing voices, experiencing bodily sensations, smelling odors, or seeing lights or beings that are not there. Hallucinations are associated with psychotic illnesses, drug use, and disorders such as epilepsy and narcolepsy.
Your symptoms are unusual and require a thorough investigation. This is especially important because the nature of your thoughts are violent and aimed at your children. I would recommend having both a medical and mental health evaluation. A medical evaluation can determine if your symptoms are attributable to a health problem. A mental health evaluation can determine or clarify a diagnosis but more importantly it can identify treatments to reduce your escalating symptoms. Antipsychotic medication can be particularly beneficial for reducing hallucinations and violent thoughts. Please take care.
Dr. Kristina Randle