You say your labs were right on target, is that according to your surgeon/PCP or did you get a copy of them and post them here? Many time patients get told that things are perfect and when they post them online here, we fine that B12 levels are dangerously low, vitamin D levels are very deficient, iron and ferritin levels are low, calcium levels are too high, protein levels are too low, this is just to name a few. These can all make you tired.
If you would like to post them, I would be glad to take a look at them. We need optimal levels in many of these areas, so just being in the normal range isn't always enough. Also, getting your thyroid levels checked is a good idea, many of us go through major thyroid changes post op