hi im on birth control and just had a baby about 5 months ago ive been having a hard time with my period being irregular i got my period all month of november then december i spotted a little january it didnt come at all and febuary i spotted a little im waiting for it this month but towards the end of last month i began feeling pressure in my lower belly as if i were being kicked i have very bad head aches im extreamly tired ive been nauseous and having lower back and abdominal pain i took a pregnanty test but it came out negative and twice it didnt show up at all am i pregnant or is there somthing elce wrong?