Advice plz

I'm gaining weight like crazy. I was supposed to start my period on the 6th of November. But haven't had anything but spotting for 2 days. And that's not normal for me. I usually have a heavy period for at least 6 days. And i have had constant headaches and I'm super tired. I took a pregnancy test yesterday and it was not pregnant that was at 12 days late on my period. Should I try again in a couple weeks?