Losing weight and losing my boobs ?!?! HELP

I’ve always had decent sized boobs, but I recently lost almost 30 lbs and although I’m super happy about my accomplishment, I’ve noticed my boobs are a little smaller. This is normal I’m sure, but I want to continue my weight loss without losing my boobs too much more. Is there a way I can prevent that, or a workout I can do to get them back ? I know I’ve heard of doing some chest workouts to prevent this. Any advice ?