take it this way:

In routine, a supervisor should use a positive,suggestive tone to solve problem. If he talk with formally, the problem is pretty serious. He got HR involved, which means that he do not think he can got problem fixed. Involving of HOUR is a preventing measurement for the future disputation. You are under a bad situation now.
One advice: never lost your cool in a job. Always try to keep yourself in a positive mode. Good luck.