16 days late???????!

I was 12 days late went in and they did an ultrasound and test all came up negative. So I thought my period would show it self, now 16 days late, cervix feels closed.( it’s not from stress, and we’re not trying so I’m not constantly thinking about it)

SO should I test again?

Also my last period was March 14 2018.

Ive never been this late. Not even when I was pregnant with my son