I've had two TKR's, 2008 and 2013. My recommendations: exercise as prescribed, ice, and not letting the pain get ahead of you. I was back to light hiking 11 weeks after the first TKR, about 8 weeks after the second. Your results may vary. Don't do too much too soon.
Your legs need to be the same length or other problems will start happening - hips, other knee, tendons, etc. Talk to your doctor ASAP about this concern.
Re the meds: During the painful period, I took meds on schedule so that the pain would not build up to being unmanageable. I reduced dosage methodically, by lengthening the time between doses in small increments. This worked well for me. Don't just stop your meds all at once.
I still do my own yard work, but find kneeling (for weeding and such) quite painful. Try some different tools. I got a Hula Hoe and often use it instead of the hand weeding I used to do.
Yes, new knees have their problems, but those problems are not usually as bad as the awful pain of the old worn-out knees.
2006 Tiger CX 4x4, 8.1 L gas V-8, Allison 6-speed