I piled it on when I had my daughter, over 4 stone but a stone went giving birth and the rest fell off quite quickly afterwards I'm sure breast feeding really helped! This time I was so ill in tri 1 that I only caught up a few weeks ago so only put a few extra pounds on so far. It's so strange how my 2 pregnancies can be so different, maybe I'm having a boy this time!
Maybe keeping a food diary would help just so your aware exactly what your eating, you could always cut out the crap stuff as baby gets not benefit from this but still have the right calorie intake with healthier options. I try to eat fruit, wholemeal toast, yogurts, nuts and cereal bars as snacks instead of junk, although I've been getting a bit of a sweet tooth lately finding chocolate raisins hard to avoid!