Level Glitch?

Hey guys, something discouraging just happened in my game. I was playing local co-op with one of my friends. And when I went to play my Hikage, who I knew was level 28, I found that she was level 5. The same thing happened with my friend who suddenly had a level 3 Asuka. What happened? How do I get my levels back? It took my some time to get Hikage to level 28.

Anyone else experience this?