15 DAYS LATE!!!!

Al

I am going on 15 days late of a missed period. I have never in my life been even more than a day late unless I’m pregnant. My baby is 6 months old and I got my first period in the very beginning of December. Now I’m so late! I took a pregnancy test the day of my missed period and three days after and even a week after and they were all negative. I have been having a TON of clear creamy discharge. Does anybody have any idea why I am so late? Is it just my period regulating itself after baby? This is my second baby and with my first, once I started my period back after birth I was NEVER late until I got pregnant again.