according to your symptoms and positive test, the ovulation might have occurred.
the life span of spermatozoa
is around 12 to 24 hours and for the ovum it is 24 to 48 hours,
as you had intercourse during ovulatory period there are chances to conceive.
start taking folic acid
tablets and multivitamin
tablets from now onwards.
once you miss the period contact your doctor and take regular check ups.