Ok you guys. I might sound like a dork, but I am confused and really need some help!

Everyone has been telling me lately that josh looks a lot like camerin. Personally, I dont think so. But my friend keeps saying that I told her brown eyes and curly hair are dominant features, and im like ok yeah I know, and she says well isnt it funny how dewitt has both and josh has neither? And a couple people have told me I should get a paternity test just to be sure. So I looked at my first ultrasound, which was august 21, 2003. My lmp was june 13, 2003, so according to that I was 9 weeks and 6 days. Well the gestational age on it says 8 weeks and 5 days, and I counted back to when dewitt and I were together (july 3rd and 4th) which was only 6 weeks and 6 days from the 4th. And I cant remember the last time camerin and I were together. (was smoking too much pot I guess) but I thought it was like late may. And from what he has said he doesnt think the condom ever broke. But I dont know. I'm not sure how off ultrasounds can be. Do you think that it was a couple weeks off? Or that maybe camerin might be josh's father? I don't know and to tell you the truth I am a little freaked out. I need some reassurance. I want your honest opinions, do you think the ultrasound was off, or that camerin really might be josh's dad?