Glad you've had your thymectomy. I remember just resting all the time, with little short, and I mean short walks, my physio said I had to walk to help with the recovery process. I walked around mum and dads small pool, starting out at one lap and building up as I felt better. I agree with Annie, sleeping slightly upright would have been better.

Mostly lost of resting, listen to your body, mine said sleep lots, so I did. Keep us informed as to how you are recovering.
take care
Kate