i had sex about 5 times during the month of december and we used a condom every time. he didn’t cum in me, he pulled out and took the condom off and then came. my period was suppose to show up on january 3rd but instead it came december 31st. my periods usually last 3-4 days and it lasted that long, but it was a bit lighter than usual. it had clots, but it’s usually enough to fill about 2 regular sized tampons a day. but this time it was only enough to fill one and a half. i took a pregnancy test on january 5th and it came out negative... could it be implantation or am i just overreacting ?