9 days late!!!

I have a normal 30 day cycle; I am suppose to get AF on December 23rd but I am 9 days late. (I'm never usually late) I took 2 hpt and got BFNs. I spotted brown discharge yesterday only for a couple hours then it stopped and I haven't had any spotting or discharge since then. I have been experiencing slight pregnancy symptoms like lower back pain; cramps; very fatigue; and a slight increase of appetite. But No signs of AF symptoms. Could I be pregnant? Did I test early? Or could it be something else?