Had sex dec 23 & 26. . had period jan 3 or 4 ( can't exactly remember ) then had sex jan 17 , 18 & 19 . edd is oct 10 could dec sex got me pregnant?

Less likely: A due date of Oct 10 would put your date of conception around Jan 17. So conception in Dec is less likely. Due dates aren't perfect. To be more specific, I would need to know how your due date was calculated. Is it based on the first day of your last menstrual period or on the measurements of an U/S? If an ultrasound, how many weeks were you when you had the ultrasound. Best wishes!