Negative tests again and again!

I had my last spotting (not periods) on 18/01/16 but my proper periods happened in 29/11/2015 but i never had this irregular spotting 11days early spotting just drops for few mins in a day then nothing! Nd now its february no spotting no periods! Am i pregnant?! As i have missed this months periods? If yes y do my hcg tests show negative so frequently! Or any idea when do i take the test again please help!!!