Am I pregnant?

Two days before AF due I started feeling really sick and got spotting. Nausea has continued and only goes away when I eat. Period arrived on time but was really light and went away after 2 days. Have tested but got BFN. Could I be pregnant or could it be something else? I’m usually on for 10 days and it’s heavy. Never had one like this before or felt sick with it. Any similar experiences or advice?