Need some answers

Madison

I ended my period on March 21st on March 22 I had unprotected sex and within 6 hours I took plan b and then 5 days later I had really heavy bleeding. My normal period was suppose to come on April 15 but that week I was stressing myself out thinking I was pregnant and then on April 17 I took a pregnancy test and it came out negative what should I do? Do I go with the negative pregnancy test?