transform.RotateAround acting strange

So I tried to make the mouse control my 3rd person camera. It appeared to work just fine at first, and it does horizontally. But when moved vertically the camera loops around the player even though on the other side the camera isnt upside down. Basically on the on the other side the mouse controls flip. Also if the mouse has been moved to face the side of the player (it doesnt matter which way the player is facing. the effect is global) it begins making circles when moved up or down.

 if (Input.GetAxis ("Mouse X")!=0) 
 {
         transform.RotateAround (target.transform.position, new Vector3(0, 1, 0), Input.GetAxis ("Mouse X")*8);
 }
 if (Input.GetAxis ("Mouse Y")!=0)
 {
         transform.RotateAround (target.transform.position, new Vector3(-1, 0, 0), Input.GetAxis ("Mouse Y")*8);
 }