Fatigue is real. Still, make sure nutrition, sleep, stress management, and exercise are solid first. Once those are dialed in, look at your doses. After that, if needed, increase caffeine. But nothing will fix the root cause.
When I was hitting the gym and running regularly I found pre-workout energy drinks useful but only used them now and then so my body wouldn't get used to the boost. I quit for a while. Now I'm thinking about starting again, this time not to push extra reps or miles but just to make it through work hours without the tiredness from the calorie deficit and the medication. Any thoughts?