I am a light sleeper also. I tried to not nap during the day, but like you, I just got irritable and gave up. The pain and lack of sleep gets overwhelming. Try to rest when you can. When I wake up, I (of course) go to the bathroom, then take a walk around the house (I am afraid I am going to wear a path through the rooms!) and it seems to relax the knee and I can then lay back down and rest. I take a diphenhydramine before bedtime with my morphine - it helps until about 3 a.m. I am careful about taking Tylenol, so I just use the generic Benedaryl - diphenhydramine.