Africans were also used in large numbers for slavery because they were easier to buy. During the beginning of the Atlantic Slave Trade, Africans were willing to sell other Africans as slaves to Europeans because they had their own system of slavery.
You could have sex towards the end of your bleeding and then actually conceive 4 or 5 days later with your early ovulation. The probabilities of getting pregnant while on your period are low, but the possibilities are there. This is not the time to have sex if you are trying to get pregnant.
Answer: It is highly unlikely that you got pregnant if your period came after you had unprotected sex. Though it is not entirely out of the realm of possibility. This is particularly true if you had your period the day after you had sex. It is important to figure out if you had your period or if you are simply having vaginal bleeding. This bleeding may not be your period but may be something else like implantation bleeding, which would possibly indicate pregnancy.