When should i stop testing?

I had light-medium spotting on the 26th and thought it was either late implantion bleeding or early period. The bleeding stopped after about a day and a half. I havent tested since the 27th early morning because i had assumed it was my period. This is my first month off of skyla so i havent had periods for over 2 years so the fact that i didnt have a "period" isnt suprising and doesnt mean i am pregnant. I feel nauseous and have headaches recently but idk if its stress, pregnancy, or maybe i just want to be pregnant so bad im having false symptoms. How many days after ovulation should i just except a negative?