What Causes Delay In Periods,cramps,nausea And Tightness Of Stomach?

Hi I m 25 i have a one year old daughter c-section I had an abortion pill Dec 22 I bled very heavy a couple weeks then lightly till Feb 16 it s now March 17 no normal period yet took a pregnancy test it was negative beenhaving some pregnancy symptoms gas moody tight upper stomach and nausea. Today and yesterday I ve been light cramping. Is it my period coming or could I have gotten pregnant again or is all this do to hormone imbalance