There are no chances of pregnancy
as you had sex on the 6th day of menstrual cycle and she were in her safe period when ovulation would not have taken place and hence no chances of conception or fertilization.
But with 6th day of menses it means that endometrium is being shed and fresh endometrium would grow
in next 10-12 days to allow any implantation.
Let us presume on that 6th day then still even if there is a fertilization
then due to inadequate endometrium, implantation shall not occur and you would still be safe.
However, you may get a serum beta-hCG
test done after 7 days after intercourse to check for hCG levels.
If the hCG levels are less than 5 ng/dL, then you are surely not pregnant