Losing weight while pregnant

Before I became pregnant, I regularly weighed 14st 7lb, not good I know as I'm only 5ft 4, but I was trying to get it down.

I'm now 10 weeks pregnancy and weight 13st 9lb, probably because I haven't felt like eating since being pregnant and when I do, I'm trying to eat healthier as I don't want to GAIN too much weight, having never lost it from my first pregnant (hence the weight I am now).

Is there anything I can do to keep the weight down? Doctors are concerned because of me having a BMI of 34, regardless of losing nearly a stone already.