Just get as big as your body tells you it wants to!
I ate very little whilst pregnant with my DD 9 years ago. I survived on cereals, oranges and the occasional (maybe once a week) meal out. However I had the most chronic hearburn from about 5 months that I was frightened to eat. On top of that I worked in quite a physical job until 2 days before I had her. As a result my DD was only 5lb 12oz and I had to have growth scans for the last 10 weeks.
This time (bang on 10 weeks) I want a huge big fat bubba lol. So am not going to worry too much about how much or how little I gain as long as I and the baby are healthy.
If anyone and I mean anyone comments on how big you are and upsets you just point out that you are pregnant, growing a whole new person in your womb and if the sight of this offends them then don't look at me, feck off somewhere else and leave me be.
The weight will come off when baby is born. I walked everywhere with DD when she was in the pram, ate healthly once she was weaned and within about 8 months I was back in my normal clothes and by 12 months had gone down a size.
Our bodies are pretty good at telling us what we need so if you crave something naughty go for it and don't beat yourself up. Your body will need extra reserves to cope with the actual birthing and recovering process and BFing afterwards. Whether you intend to BF or not is irrelevant to your body lol. And if you don't want to or are not able to BF your body will get rid of the extra naturally anyway.
Go eat a bar of chocolate or piece of cake or whatever you fancy right now!