Can anyone calm my nerves about measurements and weight gain? (Or lack there of!)

[ColorMeFamous]

I have gained a total of 27 pounds so far. I haven't gained any weight for 6 weeks now though. I had also been measuring two weeks ahead throughout the entire pregnancy and suddenly this week she is no longer measuring ahead?? I feel concerned about this but my doctor hasn't said anything. Is this normal? I guess I'm just worried because I've stopped working out and have been eating a ton and also because my mother had this thing with her babies where the placenta stopped working (can't remember the medical name) and so her babies stopped growing...