Can you fall pregnant 10 days before periods, i had intercourse on the 5th of september but on the 14th i started my period is there a chance that i can be pregnant?

Yes and No: Yes, a woman can become pregnant 10 days prior to her expected menstrual period, because her expected period hasn't come yet (it's "expected" in the future). No a woman is not pregnant if she has her normal regular period, regardless of how much sex or when she had sex prior to her normal regular period. If worried, she can do a home urine pregnancy test 3 weeks after sex.