If you're every 28 days then it's not most likely. However that's me saying that because I don't know exactly when you ovulate. Having a 28 day cycle women on average will ovulate around day 14 of their cycle which would be too late from when you had intercourse. The day you period ends if too early usually to get pregnant as it's at least another week before you're due to ovulate and the sperm would not live inside for that long to catch it and fertilise it. You need to be having intercourse around the time of ovulation to become pregnant.
Hmm for my knowledge if ur28 days ur regular so no...