Hello,
Pregnancy occurs only during the time of ovulation. Ovulation is the release of a single, mature egg from a follicle that developed in the ovary. It usually occurs regularly, around day 14 of a 28-day menstrual cycle. It is seen that pregnancy only occurs if intercourse occurs within the 6 days prior to and including ovulation. The best timing of intercourse in order to conceive is day 10, 12, 14 and 16 (in case of late ovulation) of a 28 day cycle.
So after ovulation, try to avoid these days for intercourse.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Use protection, and you'll be fine.