Suggest Medication To Get Periods And Stop Pregnancy

Hello, I & my fiance had protected sex (used condom) on 5th June. And my period date was on 16th June, till today ie 18th june haven t got my periods yet. Mostly a week before my periods symptoms starts showing like my lower body & lower abdomen starts paining but now iam not facing any such problem. 1. Is there any possibilities of getting pregnant. 2. Is there any medicine easily available in the chemist to get my periods immediately or any other way out to get my periods. 3. What can be done to avoid pregnancy at this situation. Please help & revert as early as possible. Thanks, EM.