Am sorry Lost - I went thru this with my eldest when she moved back home to get away from the meth head/alcoholic x - the calls, texts, riding around the neighborhood at all hours of the night, slashing her tires. I think we went thru a week if not more of all of the boys here sleeping in their cars waiting for him to show his face - Danny almost caught him once - good thing for him they didnt catch him, or else the three of them would have beaten him to a bloody pulp for terrifying eldest.
Unfortunately once they slip into downright crazy behavior and start babbling nonsence, its time to be concerned big time. I surely hope you went to get a restraining order, and please, keep the records of the bizarre and dangerous phone calls. Call your cell provider and change your phone number asap. Make sure someone always walks you to your car at work.
Marcie