No noticeable baby movement

In the last 2 weeks I have not had movement that I can tell 100% is baby. I have light flutters every once in a while but since my uterus stretched upward and my belly popped out I don't feel baby as well. I have an appointment Tuesday and my doctor keeps telling me not to worry that baby has lots of room to move now so it's normal but just freaked out. Any one else experiencing this or has experienced it? I'm 18 weeks