9 weeks pregnant and don't feel it :( please help!?

Oka so going by my ultrasound 3 weeks ago I will be 9 weeks pregnant in 2 days. The heart was beating at the scan and everything was fine but now I just don't feel pregnant. Call me silly but when I touch my stomach its not hard and I can't feel any difference to when I wasn't pregnant. This is my first and I'm only 17. I'm worried and would appriciate abit of reurance x