Period and Pregnancy

Can you have your period and still be Pregnant?

I'm 22yrs, had unprotected sex using withdrawal method in my safe days. That was actually my first sex. I have been having minor cramps and spotting of little blood

I'm 6 days late, this is the first time I'm experiencing such, I don't know if my period got delayed because of my first intercourse or due to hormonal imbalance or pregnancy. I'm so confused. thought I was positive but now the bleeding is coming out with severe cramps, I can't tell if it is my period or implantation. The blood is dark brown and looks like first day period.

Please help, any experience?