A: Dear b.bolter:
I agree with you that this sounds like more than just a phase. This sounds serious.
I would urge you to get professional help now with understanding what is happening and what to do about it. A professional person can be a tremendous resource--the hard part is locating that person. You might start with your own pediatrician or family doctor, and ask for referral to a child psychiatrist or child psychologist. You also can call local hospitals and ask to speak with someone who has knowledge of local outpatient resources for children's behavioral/emotional problems. Schools too may be in contact with professional people who treat children and families. Members of the clergy may also have lists of these resources. Explain that you have a 3 year old son who is very physically aggressive and that you would like a mental health professional to evaluate the problem and to offer ongoing treatment.
In the meantime, I would continue to explain to your son that you love him and that you cannot let him hurt you. Try to protect yourself and keep everyone safe.
Best of luck to you.
Elizabeth Berger MD
Child Psychiatrist and author of "Raising Kids with Character"