Hi, I'd like to help you with your question.
I am sorry you are going through this. I do not think, given what you have said, that you are being paranoid at all. Matter or fact, I would encourage you to do more about this situation.
Your husband definitely has something wrong. People sometimes lose their tempers and that is normal. However, your husband is not only losing his temper, he is becoming violent and threatening, especially towards your son. This is dangerous behavior and could end up with someone getting hurt.
It would be a good idea if you encouraged your husband to see his doctor. He needs to rule out any possible physical problem that could be causing these extreme outbursts. Then your husband needs to see a counselor. He may not be willing to go, but try to convince him (with the help of other adults in your family, not your son). He needs treatment for this anger issue before it gets out of hand.
Be clear with him. Let him know, in a non threatening way, that his behavior is scaring you and you want to help him. Then see if he is willing to get help. Go with him if you think that will get him to go.
If your husband acts out again, especially towards your son, call the police immediately. It may go against what you feel like doing, but it would be better to let the police handle your husband than to have to deal with what could happen if your husband loses his ability to control himself and hurts your son, or someone else.
If there are any other family members who can help you with this situation, particularly someone your husband trusts, see if they will get involved. The more people who can convince him he needs help, the better.
I hope this helped you,