I am still very tired 3 weeks after my breast implant revision surgery that was 4 hours long. Is this normal?

The answer is that different people experience surgery differently and have different reactions especially after a general anesthetic. There is a huge letdown after surgery from all of the emotional energy we bring to it. Once you are able to start your normal routine, this will pass.
As a sidenote, I am a proud graduate of Yucca Valley High School, Class of 1971! If you know any oldtimers in the area I probably grew up with them. 
All the Best,

Dr. J

Hi, thank you for your question.  It is not unusual to feel tired three weeks after surgery.  After receiving general anesthesia (I'm assuming this was your anesthetic since the case lasted four hours), many patients feel tired and sluggish for about a month.  You may have days or periods when you feel normal and with the regular level of energy, to be followed by periods of fatigue. I advise my patients that this effect will wear off, and that it's best to listen to your body; if you feel like taking a nap (and you're not at work), do it.  Younger patients bounce back faster, but those of us age 40+ need a bit more time to recover. If your fatigue does not resolve in the next week, please let your surgeon know.Best wishes,Dr. Naidu