What Does Delayed Periods With HPT Negative Mean?

hi i had my last period on the 11th of october and have a cycle of around 28days its now 41 days since the start of the last period. I have taken several pregnancy tests but all come out negative. i have two other children and and dont notice any symtoms of phave aregnancy nor do i have any symptoms of a period coming any time soon. Im not sure whats going on is it possible to be pregnant with a negative result and would a bllood test help?