late!

This is how my cycle has been, in September my period came on the day the app said it would. Currently, according to the app, I am 6 days late. On Sept 26 I vomited at work. I never vomit unless I have the flu, and I felt great all day! My husband and I are trying to conceive. I've taken a pregnancy test and it came up negative. When you are TTC, negative tests are a monster, and it becomes nerve-wracking to take more.  Do I go in for a blood test? Do I wait? Help!