Late period, negative test

Hey ladies. So my period is 9 days late, I’ve taken 2 test both in the last 3 days and they have both been negative. I’m a mom of 2 already (I’ve had positive test with both within a week of a missed period). I’m regular every month and I’ve been regular since removing my bc last year. I’m not stressed, I haven’t changed my eating or exercise habits. I put on a panty liner 2 weeks ago because it was pink when I wiped but that’s was the only bit of color I’ve seen in the last month. Please give me some advice on wtf is going on with my body. 😕