Could I be pregnant?

Ok so last month I didn't log my period so I'm abit unsure of when AF is supposed to start but it usually comes around the beginning of each month still no sign. My boobs are horrifically sore even wearing a bra is painful , I have a slight amount of nausea my back is aching and my fatigue is awful. Me and my SO have had unprotected sex but I took a test yesterday and it came up negative is there still a chance I'm pregnant or is it just late AF . Thanks for any advice in advance.