Can anyone answer

I had sex four weeks ago May27 and ovulation discharge around June 5-11 I tested 2 weeks after sex and a day after expected period June19 and both were negative I tested three weeks after sex and was negative this Thursday with be a month after I had sex and I should be around 15dpo or more when should I test again or am I not and the negative test where accurate I also have had no pregnancy symptoms or no period