Dealing with Gimble lock

Hello! I have the object powered by physics. Object moves along the XZ plane. I'm writing a script for camera to follow this object, so camera stays at the specific point relative to object position and rotation (actually "behind" the object).

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. public class FollowCam : MonoBehaviour {
4.     public GameObject target;
5.     public float camDistance;
6.     private Vector3 camPos;
7.     public float camHeight;
8.  
9. void LateUpdate() {
10.         float angle = (target.transform.rotation.eulerAngles.y * Mathf.Deg2Rad);
11.         float x = Mathf.Sin (angle);
12.         float z = Mathf.Cos (angle);
13.         camPos = new Vector3 (x, camHeight, z);
14.         camPos = camPos * -camDistance;
15.         transform.position = new Vector3 (camPos.x + target.transform.position.x,camHeight,camPos.z + target.transform.position.z);
16.         transform.LookAt(target.transform,Vector3.up);
17.  
18.         }
19.     }

The problem I have is then object rotates more than 90 or 270 degrees along X axis, Im getting "opposite" camera position. ("in front of the obj")
I see two options to deal with this problem:
1) Use quatrernions, but since my script based on angle along Y axis i need to get this from quaternion. Can I do that?
2) Tracking angle change and changeng the sign of camPos vector in line 14, but things like

Code (CSharp):

1. if (angle >= 270 || angle<= 90)
2. {sign *=-1;}

doesnt seem to work.