What do people think? Is it just a late AF?

I also usually have a 31 day cycle and its pretty much always been 31 days or thereabouts. I missed my period this month, took many tests and they were all neg. yesterday had a blood test and will hear back the results today...however I dont think I am pregnant b/c I woke up very bloated and when I went to the br had brown spotting. I havent had any of the usual signs of af-- no cramps...its so confusing but I guess maybe I was stressed or something. Best of luck though...Id schedule a blood test to know for sure