What Causes Delayed Periods, Bloated Stomach And Sore Breasts With Negative Pregnancy Test?

Hi I feel tired all the time,I feel sick mostly late at night and early morning and sometimes during the day,I am hungry all the time though and can't stop eating,I keep wanting to eat sweet things,I feel bloated,my breasts feel full and heavy,I keep waking up with a headache and I have had a high temperature for last couple of days.I am now 12 days late on my period but took a pregnancy test 4 days ago and it said negative.what could be wrong with me?