Confused pregnancy test

I need advice... I had my period like usual only a bit lighter that other times, I took a pregnancy test because I had an unbearable headache, and usually I only get them when I’m pregnant... taking the test at first I thought it was negative when I was going to throw it away I saw half a line. More time went by and the top part appeared but there was a gap. I’ve been noticing more symptoms like heartburn and fatigue so I took 4 more and they all came back negative. Has this happen to anyone before? And am I pregnant?