Let me start by saying that you look lovely, and I don't think you look over-busty at all!
I'll leave out all the angst, but suffice to say, I wore a D cup by the age of 14, and my size now is a 30-32DDD/F. I am 5' tall and I wear a size 2. My size does not seem to change regardless of weight loss or gain.
Some useful life-changing tools that I found, to dress down a fuller bust and bring it in balance:
I saw Oprah's Bra Revolution in 2007 (I tried to find the video online, no luck) and her recommendation of the Dream Tisha by Le Mystere, and the Enell sports bra were my start.
http://www.barenecessities.com.....&ft=1
http://www.barenecessities.com.....#038;cm_mm
Six years later, I still wear both styles on a daily basis. I also recently bought a Marlies Dekkers bra that I LOVE - great support, great fit, ridiculously comfy. I plan to buy more in the future.
The other life-changing tool was Trinny and Susannah's books, "What Not To Wear", and "What You Wear Can Change Your Life". Their advice on how to dress a large bust has been invaluable.
And wow! Imogen's post is full of great information!
You should embrace your beautiful figure, and not be embarrassed by it, or ashamed of it, or self-conscious.