You can ask to your doctor about modafinil. It's a ''wake-promoting'', not a CNS stimulant like amphetamine, drug and used off-label as a nootropic (smart drug) due to it's positive effect on energy, memory and learning. It's impact on energy is similar to caffeine in the studies. I tried it myself and had no problem on it, better than caffeine ,in my humble opinion, and also you don't have to take it all day unlike caffeine.