Welcome to HCM.
There might be slight alteration in periods, after you stop taking OC pills. I don't think presently you need to worry. There is no question of pregnancy
as you have mentioned that you did not had any sexual activity,
I advice you to wait for a week and if after that also if you don;t have your period i advice you to see OBG specialist.
Hope I have provided the information you needed.
Wish you good health. Take care.