dont worry hunny , are you generally fit and active and healty ??? if you excersice and eat really( not easy for me , i have chocolate for breakfast ...) well you bub is probably getting what she needs i put on 22 kgs with ds at 21 weeks i had put on about 11 ...
but this time i am 23 wks and only put on 3.5- 4 kgs , everything is differnt too ... unless your dangerously underweight , and you ob is worried , then id worry ..

but if your the right weight or even got a lil extra and have put on much i wouldnt worry