What should i do?

I have been working for Weis Markets for six months now. I was originally working for the local Wendy’s in town until a good friend of mine asked me if I would be interested in working at Weis as an overnight stocker. It sounded like a good idea especially since my friend was just promoted to night crew leader. Before I even filled out the application, the general manager called me in for an interview. I did complete the application and had the interview the same day and a day later, I was called back for a second interview and then I was hired.
For the last six months everything has been fine, no problems at all! But then me and my friend (who is also the night Crew Leader) had a argument outside of work, and since then, the working environment has been strained, but still always civil. Work always got done and we even talked to each other during work. Last night however, he approached me toward the end of my shift and seemed to be provoking an argument with me. He asked me about the amount of work I did and implied that it wasn’t enough. I asked if there was a problem, and he responded that there would be after he talked to the General Manager when he came in for his morning shift. I replied “Whatever”, waved my hand at him and began to walk away and he stated yelling very loudly, saying that he was going to talk to the General Manager, something that has never ever happened to be at work before. I then walked over to the aisle he was working to try and resolve our conflict civilly. When I arrived, he once again began yelling, saying things like “Get the f**k out of my aisle” and “You’re a f**king idiot!”. I honestly have never been treated this way in a workplace ever in my life. I was not only singled out and insulted, but it happened in front of fellow employees and venders coming into the store.
The worst part about this is that I had never even intended to leave my previous job until this friend offered me the job and said it would be perfect for me. Now I’m worried that my job may be at stake because of an argument between me and my friend. He is bringing what I feel to be personal conflicts and using his position as a crew leader to intimidate and harass me, knowing that if I retaliate, I would be out of a job. I have no problems with this person, other than the way he has been continually treating me for a couple of months, since our original argument outside of the workplace. Again, I do not want to have to worry about losing my job just because my friend is also my boss. My Job is very important to me.