My question involves criminal law for the state of: PA

Story goes, myself and group of friends are outside getting ready to leave a bar when I hear someone make the comment they are going to "kill the guy in the white shirt". I turn and see an individual I do not recognize walking towards us and notice that he is talking about a friend. My friend confronts this individual about the comment because he has no idea who this person is and this person begins instigating with the typical f-u p**sy and what are you going to do etc. I'm standing there and the guy looks over at me and asks what I'm going to do and he'll f me up. I just stand there and another friend steps in and tells the guy to just shut up and leave and begins pushing him away. The guy continues to call us p**sies and f-u and we just keep telling him to leave. Guy gets punched in the mouth by person trying to get him to leave and goes down. Person who punched him walks away. The guy gets back up starts walking towards us and again starts calling us p**sies and asks if thats all we got etc. Another friend tells him to leave and the guy starts walking towards him still running his mouth and gets hit again. Guy goes down gets back up and starts walkin towards me and the individual who just hit him who now has his back turned to the guy and the guy again starts running his mouth. I had enough, hit the guy, guy doesn't get back up. I leave, guy has a broken nose and files simple assault charges against me and the 2nd individual who hit him. I still haven't received my charges yet and didnt' know what I was being charged with until I read it in the local paper but I am going to talk to a lawyer as soon as I receive them. I have no record and I am stressed out about what I might get. Any ideas?