One of my rats has been acting weird

I have two rats and the older one is more social and will climb onto my hands but my younger one is still kind of timid and doesnt like to be picked up. When I put her in a new environment she freaks out and starts running in circles over and over and gets nervous and poops. She had an ear infection which made her tilt her head but we got that treated. I think that's when she started acting like this. When she's free roaming in the bathroom she's running around frantically and whipping her head around. I couldn't get her to keep still but I did feed her a few rice krispies. Meanwhile my older rat is fine free roaming and she runs around and explores but not in the weird frantic way that my younger rat does. Is this a normal behavior of a shy/ anxious rat ? Or is it a symptom of something else ?