This last contact...showing up at your door at 11:30 p.m., and then the email this morning, are signs that he is still obsessed with you.
I hope you didn't answer the email, but if you did, let it be the last one!
Follow the advice given here to block future emails from him.
The obsessed stalker can be very manipulative, as revealed in his email this morning, stating he is "coming to terms" with his thoughts, while at the same time...worrying you! These types can even manipulate to make you feel this is all YOUR fault! Don't fall for it, and don't be his victim! Be safe, and call the police if he shows up at your door again.
Patty