I agree with both ladies...
They are probly right you should not have got a positive preg test 6 days after being raped.....you had to of got pregnant before that. Early ultrasounds are very accurate....if the first day of your last period was sept 11th and you have 28 day cycles you should have conceived sept 21st- the 27th. Not oct 10th. The earliest a test will usually show positive is 9 days after conception.
You wouldn't get a positive pregnancy test 6 days after the rape, you would have had to have conceived at least 2 weeks prior to you receiving a BFP. I'm so sorry you had to go through what you did i can only imagine how you must have felt.
If your last cycle was 11th Sept you would have ovulated Sept 15th on a normal 28 day cycle. I've counted back and from the 11th Sept you would be 6 weeks +, i wish you all the luck in the world with your pregnancy