Yes, after 5 years of Tramadol you heavily depleted your Serotonin and Norepinephrine levels. You also possibly depleted your dopamine levels too because Tramadol is a weak opioid agonist. That means your 3 main neurotransmitters are depleted and yeah, that will cause extreme lethargic feeling. The best way to help that is to take these two supplements and they should help a lot:
#1: L-Tyrosine. This increases dopamine and Norepinephrine and for most people will increase their energy and mood. Being depleted in either dopamine and/or Norepinephrine can EASILY cause you to feel extremely lethargic. It works best taken in morning with no food and rather just Juice as a carb source. Many people feel it working within a few hours while other people it might take a few days or longer. Also I believe Vitamin B6 and Vitamin C are needed for L-Tyrosine to be absorbed properly.
#2: 5-HTP. This increases Serotonin. Since you probably heavily depleted your serotonin levels from Tramadol this also is very important to take. Low Serotonin also can cause you to feel very lethargic it's a common effect of low serotonin.
#3: You need a good multi-vitamin that has all the Vitamins A to Z in it because not only do they help your energy and help you feel better, but they also are required to help the L-Tyrosine and 5-HTP absorb properly.
If you take the L-Tyrosine and the 5-HTP both DAILY + take a good multi-vitamin (think something like EmergenC packets that have all the Vitamins A to Z) then that is the best combo and best bet. You need the vitamins for your body to properly absorb the L-Tyrosine and 5-HTP. Also they will help with energy in general, but still they are important to take to make sure the L-Tyrosine and 5-HTP absorb properly. L-Tyrosine is best taken in the morning with no food but rather just Juice as a Carb source, while 5-HTP is generally taken at night. You could take them at the same time if you wanted. All that really matters is you take both of them + multi-Vitamin, as you want to increase all 3 of the main neurotransmitters as all 3 of them are very very likely depleted after 5 years of Tramadol.