As arthuro said, please give more information so we can help you.
In the meanwhile, check the way you give velocity and angle to the bullets. You have to rotate them 180 degrees if you wish them to move left. Or you could add a negative force to a non-rotated bullet. That’s as much as I can do without any more info.
There is a simpler way using top to down movement. Instead of animation, it may be easier for you to base the direction of the bullet on the angle of your character. Each bullet created must have the angle of the character at the time it is created and its movement force must be based on the angle of the bullet created (which will be the same as the angle of the character at the time the bullet was created).