Phoenix924

I'm afraid of the 5 hour energy drinks myself. The ones I have seen as loaded with caffeine, which acts as a diuretic. Since most of us struggle early post-op to get our liquids, I wouldn't take the drink. Instead, concentrate on getting your Water and Protein in, and make sure you are taking adequate Vitamins to help meet your nutritional needs. I specifically recommend B-12. I take a sublingual B-12 every day and I can feel the difference in my energy level when I miss it for even a day.
Look at your Vitamin regime and see if there is something you are missing. I take a Multivitamin, B-12, Biotin, and Calcium every morning, plus more calcium and an acid reducer at night. I have other meds I take by prescription as well.
You might also benefit by talking to a nutritionist or dietician about adding more carbs to your diet. Carbs are necessary to give you the energy to work out.
I have to add that I've had very little problem with low energy or exhaustion. I woke up from surgery feeling like a new person and that hasn't changed for me yet. However, I have seen lots of people who are tired, just from the healing process itself. It takes about 6 months for the stomach to completely heal.
Good luck! I hope you find the solution quickly.