Hi, I Am Getting Married On 19th Feb. My Periods

Hi, i am getting married on 19th feb. My periods have been irregular and I am on a 20 days cycle as compared to the 30 days cycle since the last three mnths. I need a medicine to prolong periods for this month and also a safe contraceptive option. I heard that all contraceptive pills have side effects and only saheli does not. But saheli is not available jn the market. Please suggest.