I am confusion

I’m 19 days late, according to all of these calculations on the apps, I should be 6 weeks pregnant, I tested and got a negative test but I’m never late or miss a period, I have every symptom possible, I feel it in my gut that I’m pregnant but the test are saying otherwise. I’m so confused. Also my first pregnancy, I didn’t get a positive test until I was in the middle of my 8th week. Shall I just wait it out?