I can't see my nipples

I'm only 24 years old and I can't see my nipples! My boobs are a little saggy because I'm a 38C and their shape is where my nipples kind of point down a little so when i take off my bra all I see is above boob and I just realized how much it bothers me today. I also sleep without a bra every night and if I'm home all day im braless, I hear that can cause your boobs to sag because of gravity and what not, does anyone else think that's true? Ugh I guess I'm just ranting and hoping to hear women empowerment speeches and such. I'm just really feeling down about this. I also heard if you flex your pectoral muscles, work them out like you would any other part of your body, it helps with the sagging, anyone else head or try that?