Could I be pregnant or is my body just tricking me?

I was expecting my period on may 3rd, I had slight cramping, sore , increased urination...fatigue, adn a backache.....but NO period....so I took a pregnancy test yesterday, unfortunately it was around noon so it wasn't first morning urine or anything, and it came out negative..... I haven't really been having cramping but i'll get small twinges every now and then, and my are still sensitive....and im exhausted...even though the test was negative, could I still be pregnant? If I am I would be 4 weeks 4 days, would that be too early to show + on a HPT.....?