I am a 24 year old female. My boyfriend and I are not trying to have a baby but we do have unprotected sex. I haven't had my period since Aug 12th that's 13 weeks. I have had negative pregnancy test (the pee test) at home and at the doctors. I have also had a ultrasound to see if I have cyst and it was negative. My stomach is swollen and hard on the top. I just went and got a pap my doctor asked me if my stomach hurt and it doesn't however it really big I look like I'm pregnant. I don't think I am but the doctors don't thinks its anything wrong with me. There answer is they can give me a shot to have my period but I feel like something could be wrong. I also gained weight in the last few months and I've been eating healthier and working out so I should be losing weight. I have also been very tired. Any one know what could be wrong?