I am a thin slim build. i never had a big bust but i am losing what i have and i don't know how to stop this. how to stop it?

More to the story?: Have you recently had a baby/nursed, etc? Breast tissue can vary with weight fluctuations; they get bigger if you gain - but so does the rest of you. You can build up the pectoralis muscles underneath the breasts, and that may make your breasts appear larger. But if you are seriously unhappy about this, make an appt with a reputable plastic surgeon and explore your options. Good luck. Lgromkomd.