What your snake was doing is definitely not normal. Make an appointment with a reptile vet ASAP.

Please... separate your snakes, especially since one may very well be sick.. you don't want two sick snakes, do you? In spite of how cute they may 'look' together, snakes are stressed when they have to live with another snake. It is not unknown for ball pythons to eat each other either.

Keeping mice in the same room shouldn't make them aggressive, just make sure YOU don't smell like a mouse. That means wash your hands REALLY good after touching the mice (I made the mistake of not doing that once. oops)

They won't stay aggressive because of the mouse smell.