I am in the exact same boat this month. Normally 27-28 days, this month I'm on cd 34 and still nothing and all negative tests.
For me, I'm not married so I know it's not an issue of pregnancy. It's something else, but I don't know what it is!
I suggest you wait for another week, if the tests are still negative, you should console a doctor!
your menstrual cycle can change from 28 days to 35 days or even more. my cycle is usually 28 days but for a couple of months due to stress from college and work it changed to 34- 35 days. your probably stressed out.
I thought about this before. But the thing is when I'm stressed it comes even faster ( in 25 or 24 days.) Which happend in my last period, but this time I'm very calm!!!