Hi Becca,
I gained the weight in my 3rd trim last time just cos of my diet I wasn't really eating healthy just eating the food I fancied and thought I would lose the weight afterwards but its not that easy.
The kind of stuff I was eating was few take aways each wk, fizzy drinks and the odd chocolates alot of the weight went on in the last mth of pregnancy I was 2 wks overdue so that didn't help and my baby was quite big 9.6lbs.
I wasn't well after my section I was dehydrated and my babies sugar levels were low so the midwifes tried her with formula just toget her sugar levels up and she wasn't a very hungry baby and went down to about 8 lb. But generally in last trim alot of weight you gain is the fat stored for breastfeeding and cos I didn't really bf the weight fell in the first 2 wks I lost about 18 lbs without dieting but you can lose weight by bf too.
It just depends on the individual when you gain weight during pregnancy, with my first baby I lost 2 half stone in begining of pregnancy and only gained stone of that back on my baby weighed 6.10 lb so after birth I felt amazing I was up walking around after my section alot sooner.
I really don't think you need to worry I remember you saying your only 11 stone so if you only do gain about 2 stone or even a bit more your probably beable to lose that weight quite easy as baby, fluid, blood placenta can weigh a stone or more but when your baby arrives your be so happy you won't be worrying about weight x
