The last time I had slept with my ex was Sept 19.08 That month I had a funny period it was brown and my hair started falling out alot more the usual. October I did not have a period. On November 3.08 I slept with someone else and did not use protection. I went in for my ultrasound two days ago. Finally when the man never assured me the baby was fine or anything I asked and he said from his point of view it looked fine for right now, at 17 weeks. I questioned him then when my last period would have been and he said he didn't know. My doctor three weeks before measured my uterus and it measured 18 weeks and my stomach measured 17 weeks. The man doing the ultra sound had me in the room about 20 minutes he kept measuring the baby about four different time which got me worried, but he never said a word. Finally he told me did I want to know the sex and he said I'm having a girl, which I was so sure I was having a boy. If I did the math correctly 17 weeks back including this week would make my last period to have been October 23.08 which can't be possible. Is it possible that the baby is 3 weeks smaller then it should be. I just started taking prenatal vitamins about a month and a half ago. And before I was sure I though I was pregnant I was partying pretty hard. I want to know which guy could most likely be the babys father? September guy or November guy?