Am I Pregnant??

So I’ve definitely had unprotected sex several times this month. My period is now 6 days late. I had light brown spotting 16 (!) days ago, and I took a pregnancy test this morning just to be safe. It was negative. I’ve been extremely tired the last 3/4 days but other than that feel normal. I don’t know if my period is just being erratic for some reason or if I could actually be pregnant Has anyone else had hpt show negative when they were actually pregnant?