15 dpo & late

sid

So i was supposed to start my new birth control this month & so I’ve been waiting on my period for a while. I havent had any cramp at all this cycle & i got on here this morning & saw that i was a day late for my period. I had light brown & bright pick this morning when i wiped & i thought it was Aunt Flo so i put a tampon in but when i went to change it, it was completely dry & I’ve had nothing since. Took a test this afternoon & it was a negative. Anyone had this happen and what was the outcome??