Pregnant or not??

Hi!
I have a question because I'm not quite sure what's going on. My partner and I really want kids, and I stopped taking the pill a year ago. My period started on Feb 4th, but it was very light—just for 2 days. On the 3rd day there was nothing at all, and then on the 4th and 5th it came back. I was supposed to get my period on the 5th, but it didn't. Now I'm 3 days late and my test is negative. I do have pretty bad period cramps, like it should come through, but it's not.
I'm feeling really unsure right now.