You cannot be pregnant yet, but you could be about to become pregnant. A blood test needs to be taken once you are pregnant.
Assuming a 28-day cycle, with your last period starting 1st Nov, ovulation is likely to have taken place 15th Nov, and so 12th Nov is reckoned to be a fertile day (sperm can live for 5 days in a woman's body). If an egg were fertilised, the embryo would likely arrive in your uterus tomorrow (21st Nov) and implantation would possibly occur (pregnancy start) by 24th Nov.
If you have 30-day cycle, the dates move by two days. Then the 12th Nov could possibly be a fertile day.
Hope this helps