Why am I late?

Arolynn

So today makes 8 days and still no BFP. I'm having mild like cramps. No spotting no blood. And no other symptoms. I think I took 4 FRER tests over the last week and they were all negative. What is going on? My period has been regular, ranging between 28-30 days. I'm traveling for work and I won't be able to get a doctors appointment in a while. So please share some insight.