Why Do I Symptoms Of Pregnancy Even Though My Pregnancy Test Showed Negative ?

Am 31 yrs old and my last period was on 16th april usually am 21days between periods had sex with my partner on the 31st april and by the second week of may l started having breast tenderness and itch nipples,started mild cramping with bloating , nausea ,light headeche,tired, mood swing and my knees has been painful my period was late till the 34th day,l bleeded heavy with clots and a sack like,pinkish,purplish and greyish colour,l bleede for only 2 days normally 3to 4 days and had lots of pain by the second day by the 3rd day hard a little on the pad for the whole day hardly changed it with mild cramps l tested negative for pregnancy what can this be and what can l do?