Trip to the doctor?

Soooooo my periods are typically regular. They’ve always shown when they’re supposed to. Except last month it was 4 days late. I haven’t had sex since before my last period. My current period is now 6 days late. I usually get cramping and spotting and have an emotional breakdown every 5 minutes before my period comes, but I’ve had none of that. All at home tests are coming up negative. I’m not feeling stressed and I’ve made no lifestyle changes. So my question is, when should I go to the doctor to find out what’s going on? Like how late should I wait to be?