Someone help please !

Courtney
Having mild cramps & have a headache & extremely drained . Feels like AF is coming but it's not due till March 9th ! Took an ovulation test on the 21st of February and it came out positive . I took another one about an hour ago thinking maybe the test I took on the 21stvwas wrong but the test I took tonight came out negative .. Idk what it could be ??