Yes. There is going to be some hormone imbalances for some time. You had your last period on 15 March. By a 29 day cycle you should have got your next period on 13 or 14 April. But you had sexual intercourse on 12 April and I pill thereafter. So the natural fall of Progestone which was occurring suddenly got boosted on 12 April and your periods got delayed.
You could have had withdrawal bleeding around 23-24 April but it did not happen.
You should get a
beta HCG level done. If the level is at "not
pregnant range" then withdrawal bleeding can be attempted. But it is also possible that you may be pregnant.
Please consult with a Gynaecologist with the beta HCG level.