Fps Camera rotation very choppy and jittery

I'm extremely new to unity, and I'm trying to make a simple character controller with a rigidbody, but my camera movement is so extremely laggy.

 void Look()
     {
         //Gets the mouse input and multiplies it by the sensitivity
         float horizontal = Input.GetAxis("Mouse X") * sensitivity;
         float vertical = Input.GetAxis("Mouse Y") * sensitivity;
 
         //Variable which keeps track of the rotation of the camera on the y
         yClamp += vertical;
 
         //Rotates the camera and player
         camera.transform.Rotate(-Vector3.right * vertical);
         transform.Rotate(Vector3.up * horizontal);
 
         //Prevents the camera from rotating upside down
         if(yClamp >= 90)
         {
             Clamp(camera.transform, 270, "x");
             vertical = 0;
             yClamp = 90;
         }
         else if (yClamp <= -90)
         {
             Clamp(camera.transform, 90, "x");
             vertical = 0;
             yClamp = -90;
         }
     }
 
     //Clamps the rotation of a given transform on the given axis by the given number
     void Clamp(Transform obj, float value, string axis)
     {
         Vector3 eulerAngles = obj.eulerAngles;
 
         switch (axis)
         {
             case "x":
                 eulerAngles.x = value;
                 break;
 
             case "y":
                 eulerAngles.y = value;
                 break;
         }
 
         obj.eulerAngles = eulerAngles;
     }

Any help is appreciated, thanks in advance.