Just confused help me please!

So about 2weeks ago I was experiencing real bad breast tenderness which I took as maybe I was pregnant cause they hurt more then usual. But then I woke up with almost no breast tenderness & I started what seem to be my period last Friday sept. 11 it lasted 2days medium bleeding and spotting on the 3rd day then nothing today my periods normally last about a week and with fair bleeding all the way through. I also still feel bloated and cramping like my period is here. I have also had a sharp pain on the left side of my abdomen which is on and off, an extreme headache and mild nausea. I took a pregnancy text today at about 8-9 am and it was negitive.  Has anyone else experienced this or something similar? Should I be worried?