Me And My Girl Had Sex On 7 21 16

Me and my girl had sex on 7 21 16 she said she had her period threw 7 10 16 - 7 16 16 and didnt have sex with her ex or any one two weeks before that.and she pregnant and she write her periods and whens she has sex down and she also went to the doctors they said she was 6week and 6 days wich means she concieved on the 7 14 16 em i the father i also wasnt there for the doctors appointment..i need help