Hi Holly, my surgeon told me to sleep however was comfortable straight after the op and not to worry about sleeping upright or back sleeping. I found it most comfortable to sleep upright for my boobs the first week anyway, then moved onto my back at about 9 days. Then I’ve been sleeping on my sides from 13 days, I put a pillow under my boob just to support it a bit. So don’t worry too much about it. I’m now 3 weeks today xx