Late period

Okay so my period is late 11 days. I've already taken a test it came up negative last thursday. I don't have any early pregnancy symptoms. My boobs are not sore I'm discharging a little more then normal but nothing too alarming. I wasn't afraid at first until I told my boyfriend and he said the Saturday before last he made a mistake. After he came he went down to finish the job with me and fingered me while he ate me out. And he had just cleaned up with his "cum rag" I'm freaking out I'm too young to be pregnant. I'm graduating high school this year and my older sister JUST had a baby. If her 19 year old little sister is pregnant too I'm going to be shamed out of my home. What should I do???