Is it normal to still be exhausted 8 weeks post op breast reduction/lift? No complications but still zero energy. 47 yrs old

In fact you may be malnourished.  I find that the patients would not meet their calorie or protein goals early after surgery without specific counseling.  Although you may want to diet, you may be in need of some nutrition.

In my opinion, assuming your breasts healed as expected, at 8 weeks postop from breast reduction surgery, you should be back to your baseline energy. Best to make an appointment with your primary care physician for an exam to make sure there is no underlying health problem.

You may want to check some lab values to see if you lost enough blood from the surgery to become anemic.  This may explain your lethargy.  Starting iron supplementation will help if this is the case.

You body has gone through a major surgery and it takes a lot of energy to heal. So it is not uncommon to be tired and weak.  You should see your doctor to make sure there is nothing else going on, such as an infection or a seroma.

Yes, it can happen.  I remind my patients that anesthesia can stay in your blood stream for weeks after surgery.  Keep in mind it can make some patients feel depressed as well.  Walking regularly can help metabolize the anesthesia gases out of your bloodstream.  

It is not uncommon to be tired even 8 weeks after surgery.  However, you  might want to check with your doctor to get a check-up to make sure that your labs are ok as well and that you are not anemic.

Everyone recovers differently.  Make sure you are well hydrated and that will make you feel better.  My patients that feel the same way have improved with hydration.  You had a major surgery and it takes time to recover and don't forget to relax.  Maybe you went back to work too soon.