implantation

Okay so with my first pregnancy I had pink spotting, one time and I knew I was pregnant and had a positive test later that same day and was 5 weeks pregnant.  I always was surprised how early on I got a positive and think that was out of the norm.  This morning what do you know I had the same pink creamy discharge and I have one test and don't want to waste it! How soon after spotting would you ladies say is a safe bet to take the test for an accurate result!?