Scooby, You've described the man in crisis. They become very paranoid and yes, they lock doors to the bedrooms and bathrooms when they are changing clothes, etc. In their mind, we have either become the "authority/parent" figures or they feel they are cheating on their OP's if we see them or touch them. If you think back, when you became a teenager, you became very private about your room and didn't want people to see you changing, etc. He's in the teenager stage and boy is he having a time of it.
Please remember that he is operating on emotions and is not truly rational about anything. Sure he gets panicky. He doesn't want you to have fun while he's miserable. So, what do you do, turn the phone to vibrate while you are out and not answer the phone if you see it's him. He'll get over it or he'll blow a blood vessel. He doesn't want "mom" out of his sight because that must mean she's got a life and having fun. It's really a control issue and only you can stop it by not responding and ignoring those texts. If he asks later about it, be honest and tell him you were busy.
Set your boundaries and one of them is the draw the line in the sand the next time he speak to you w/disrespect. Advise him that you will not tolerate or deserve to be treated disrespectfully and that when he calms down you'll be happy to discuss whatever has him wound up. You have to be the one to take back your control. The longer you allow this behavior, the more he'll test your limits. He's a baby having a temper tantrum. What do you do in that case? You certainly don't reward bad behavior w/attention, etc. You put them in time out and leave them be. Walk away when he's acting disrespectfully.
Go dim, go about your business and continue to live your life. Leave him to stew for a while.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.