What the hell size did you buy? Lol

I'm a typically small person (short and small) and a size small would probably fit me prepregnancy. But now I have no idea what size to buy. The sizes on them said that the chest size for a medium was 39 inches... currently my stomach is 42 inches and I have almost 9 weeks to go haha

How much bigger did you order yours if you already have yours? Or what do you recommend? I am hoping to be able to wear this after pregnancy too, but I'm not sure if that's going to happen with the size issues. Thanks!