At 18 years old having a low sex drive is probably a good thing, sorry to sound like a mother ( I am only 25). But, I give you credit for realizing the importance of using birth control pills. I have heard that different kinds of birth control pills can decrease your sex drive. As a matter of fact my doctor told me that if he told me all the possible side effects of birth control pills that I would not want to take them. A few days ago I was walking through my local drug store and looking at the herbal remedies and saw a bunch for low sex drive. I would caution that you make sure whatever you take will not interfere with the birth contol pills though.