im 18 years old and im 13 days late from my period.also, my last months period was spotting for 3 days and then kinda heavy for one day usually im medium for 4 days. lately i have pressure above my lady spot and sharp pooping and gas pains and i have cravings and im always tired after a full nights rest. i have hunger pains all day even ater i eat as well. i took a home pregnancy test 3 days after my missed period and it came back negative. whats up? am i pregnant?( i dont have insureance so no doc visits)