Hi I Am Mrym Am 26 Year's Old Am Married

Hi I am mrym am 26 year's old am married i have two kids first daughter and then son after 7 years i miss my period i have unregular period problem but it takes only 5 days I had my last period on 21.2.2016 and finish at 25.2.2016 now today is 11.4.2016 I have crump in lower tummy headache food craving mood wings heartburn pain in lower tummy but my home pragnanci test which take 2 days before is negative why? I have no nosia