Hi I went to the doctor today because my stool has blood in it. I weigh 103 pounds and I'm 5'9 and 18 yrs old. I was told that I was dehydrated and that I needed to gain weight. I've not had my period for about two months. The doctor said that I needed to make sure I wasn't pregnant before I started taking the dietary supplement prescription. He told me to pee into a cup and he took it with him and returned 15 minutes later with a prescription for the dietary supplement. Am I pregnant? I haven't had sex before but my boyfriend and I do about everything else.