How do i stop my dog being so scared?

I have two dogs that are the same age and they recently started fighting and its getting really bad (loosing blood, cuts and hurt bones etc.) and now one of my dogs are shaking really bad and everytime she sees the other dogs she starts hiding behined me and snuggling in my arms and runs with her tail between her legs wont settle!! PLZ TELL ME WHAT IS HAPPENING AND HOW TO FIX THIS!!