iPhone screen upside down

Hi.

My iPhone 5s (iOS 8) is having a crazy issue.

In certain apps like facebook messenger for instance, when I open the app, it opens upside down. I need to rotate the phone 180º so that I can see it correctly.

As you can see in the picture, it's really strange. Some things in the app appear in the correct way, the same happening with the system silent mode notification.

This does not only happens on an app, it also happens with SMS notification bar, etc.

Does anyone has the idea of what might be happening?