16 days late but negative tests with 1 faint positive

i absolutly feel pregnant. my breats and nipples are so sore i can barely touch them, im bloated, extremly tired, breaking out, moody, get random jabs all over my stomach, increased discharge. 16 days late for my period and the only blood i had was the day my period was due and it was pink when i wiped.

i have taken 3 tests, w came back negative and 1 came back faint positive and then disappeared.

I have 2 healthy boys so i definetly know what it feels like to be pregnant...

Why is it not showing up on a test??