Can I get pregnant if I had unprotected sex 3-5 days before my period comes?

I'm not sure about the science behind how many days before or after would be most likely to get you pregnant.
So, i'm no expert but I rate any unprotected sex could possibly lead to a pregnancy.
Stressing about it wont help you though as stress tends to affect your period and may delay it with a couple more days if you stress too much.
Try to relax and wait to see what happens and if the suspense is killing you, invest in a cheap home pregnancy test and get results immediately.
Apparently these days those home kits can tell from being just one day pregnant.