The easiest thing to do is to simply skip your period. I assume that when you say "start taking medicine" you are referring to your birth control pill. If this is the case, then skipping your period is easy and safe. To be 100% sure you are doing this correctly, please check the information that came with your pill or Google your pill's name on the internet to confirm which pills are the "placebo" pills. In general, the last 7 pills of the birth control pills are placebo. They contain nothing. What you are doing is essentially stopping any real medicine and this is what starts the period. What you you do is simply not take those last 7 pills, but instead start a new package early. Depending on what type of pill you have you might get some spotting, but generally this should work just fine.