please help..18week pregnant

Shruti • Abhishruti

I am exactly 4months and 1week pregnant...but I still don't observe any sort of baby moments...and neither I have my pregnancy belly...its my first baby...though I had my first ultrasound three weeks before.. yet I am worried..... even my weight is decreasing instead of increasing.....please if anyone there can help me out.... with how should I react to it. ...family members says I am quite tall thats why. ..