worry I think build has a lot to do with it - I'm not skinny and I'm actually fairly broad, but I am short in the torso and have hypermobility and a fairly strongly curved spine, so I show pretty early - 14.5 weeks here and it is completely obvious to all.
I had a very petite colleague (teeny tiny bones, pelvis and ribs) who kept it more or less private until she started showing at 8 months - she must just carry further back than some women. Given what you've mentioned, there's nowhere for the bump to hide, or go, except out - I'm not surprised if you're showing already
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I had an ED as a teen and while I'm more or less ok now, I lose my main sources of exercise in pg and balloon with water weight due to gestational hypertension. I am frigging enormous in pregnancy but I just have to keep it mentally separate from my everyday self - the baby is more important, I will need strength and health after the pregnancy too, and from previous experience the weight will go away quickly with a bit of effort.
Do you have someone to talk to about the changes to your body, the lack of control etc? I know you have talked about wanting to try to BF and your weight being a factor. I'm not an expert but if I can ever help talk stuff through I'm happy to do so. SIL has been in the grips of ED in recent years and I know consuming it can be.