Everyone is different. If you menstruate normally, I'd guess your hormones are okay but it never hurts to check. It may just be the way you are built. But know that our breasts change over the years. Mine look a LOT different than they did in my teens now in middle age and two kids later. You can try some chest muscle exercises which can help a little. And bras these days make it so you hardly know when you are in clothes what the real size of a woman's breasts are. And there are as many men who could care less about breast size as there are who love large busts. Try not to worry too much.
Well, you could ask your doctor to run hormone tests. I wish you didn't hate them, though. You almost certainly don't look like a boy, you doubtless look very feminine. (Think of how pretty some women are with pixie cuts, the contrast of their female face and short hair makes them look spectacularly lovely.) Women's value is not measured by their boobs, thank heavens. If you haven't met men who like you just fine no matter what size your chest is, you're meeting the wrong kind of men.