Im needing some help please?

Oh Geez, I am so confused!! I been reading here on 7 week pregnancy's where they see more than a sac. But when you are 7 weeks, you are actually 5 weeks baby development right. So all you would see is a sac. When I went in at 7 weeks there was the sac and the doctor says maybe its too early to see anything else. All week been feeling twinges here and there and pulling. Little annoying stuff. No pain though. Give me your insight please