I found 5 weeks post-op I seemed to go backwards. I used to wake up wondering where my aches and pains would be that day. Hang on in there, it's still very early days and it will get better. As for sleep, try not to stress about it. I slept when I could, read my kindle, played silly games on the iPad, probably spent too long on the forum when I was awake and managed the odd power nap in the day that seemed to help. It's definitely not a linear recovery, so expect some backward steps and I'd say just walk as far as you're comfortable. A friend used lamp posts to extend his walking after TKR, extending by one lamp post a day. I hope things start to improve for you soon.