Wanna cry

So I have a roommate who is 21 years old has a part time job can barely take care of herself doesn't pay for rent we buy all of her food everything we're helping her out she parties all the time and sleeps around which there's nothing wrong with I did it when I was single too just asked me for a pregnancy test and went to the store to buy one because I was out because she might accidentally have gotten pregnant she doesn't want a baby doesn't need one can't afford to take care of a baby but if she's accidentally pregnant and I've been trying for 15 months I'm going to feel so f****** broken how am I supposed to walk around and be around her every single day knowing that it just was that easy for her and I can't get pregnant how do you even deal with that