I am suppose to be 12 weeks. Took two pregnancy test and they were positive however when I went to my ultrasound when I was suppose to be 8 almost 9 weeks the ob said I was only 4 and 5 weeks. The next appointment, a week later, the same thing. My last period was October 18th. Its now Jan 15th. And my last appointment we finally seen heartbeats. My ob still couldn't tell me how far along I am. I have no due date. Also I am pregnant with twins. I am assuming I am 6 to seven weeks really and am really confused with what's going on in my body. I WOULD JUST REALLY like to know how far along I am. I am an ultrasound pic of both twins can someone give me an idea. I can send pics to someone's email. It won't let me post them on here.

Twins are harder to tell. All dating of conception is based on average size of fetus compared to normal sizes of other fetus at certain times.

Even the best dating, is still off, give or take two weeks.
So there is no exact date, will never be an exact date that is really correct.

If you know your last period, then conception happened sometime in the four weeks following the last period. So you can narrow it down to that time frame.

As you get closer to delivery they will determine more a exact time that delivery should happen.

Know all that. But the dates aren't adding up. My last period was October 18th. I took two test sometime in beginning of November. Both came out positive. Then my first ultrasound I should have been almost 9 weeks. But then doctor said I was only 4 or 5 weeks. And of course I started to freak because I was a month behind for some reason I thought it was a miscarriage. Made appointment for the next week for another ultrasound and again the same thing. My ob said I was only 4 or 5 weeks. Then the third ultrasound the same thing he said 4 or 5 weeks but now he says there are heartbeats which is a good sign. So I knew it wasn't a miscarriage. But how can the tests come out positive so soon and have pregnancy symptoms and the babies supposably were just conceived doesn't make any sense to me. Very confusing! I thought You had to be at least 6 weeks to see a heartbeat. So I am assuming even though he says I am 4 or 5 weeks I have to be at least 8 now since its been 2 weeks since my last appointment. Thoughts? And wondering why my babies are so far behind my period. I haven't had a period since October.