No period but negative results

My boyfriend and I had unprotected sex in March, 4 days before my period started. I received my period as expected, but it lasted 5 days (usually lasts 7). I didn’t think anything of it. I missed my period for the month of April. I took a test 4 days after my expected start date but results were negative. I waited again and took one ending of the month, April 29th & still negative. I’m experience no stress, but I’ve experienced cramps like I’m about to get my period. Have any of you lovely women experienced this? What was the overall outcome or how do I move forward??