Since you had a normal period after the incident, it is obvious that you did not conceive. If you have had an intercourse after that and always had regular 28-30 day cycles, indeed you should be worried about the possibility of pregnancy
. Otherwise, you should see if you skipped a period as happens once in a while due to temporary hormonal
imbalances and go for further investigation to rule out hormonal or other derangement leading to the situation. Please see a specialist for further help. Take care.