Going on 7 days late. BFN...

I am not stressed and got a negative hcg level blood test and urine also had an internal and external ultrasound done and no baby was found. Wouldn't it show up on a test by now? I am only going to be 28 I should still be getting my period its never been late except for the two other times ive been pregnant.. What do you all think? And also my tubes were severed and burnt closed in 2017. Yet i have no period and all these tests are coming out NEG. 👎😞 btw: I regret having my tubes tied just to clarify things lol.