What will happen to me and possibly my car/insurance if my friend got pulled over driving my car drunk, and I was the passenger?

He was given several sobriety tests, and eventually taken to jail. The police kept my license and registration and took it to the jail where he was incarcerated. I was ordered by the police to find a ride home. The next day I had to pick my properties up at the jail. The police never identified themselves to me, and did not tell me I was under arrest. My car was not impounded, either. They do have all my information, though. Here at PA.