I only had 1/4 the breast taken but the pain and all the rest of that mess in the first couple of months resulted in a lot of lost sleep for me, partially because my mind would roll everything over and I didn't seem to be able to stop the thinking. I found that listening to soft instrumental music helped quiet the noise. I'd make sure I had left time for painkillers to have started working before I even tried to sleep and had a few extra propping pillows on hand for the inevitable tossing.
Have you spoken about this with your GP? If it's driving you totally nuts it might be worth getting a sleep aid. Hope you're sleeping well right this minute!