I get that tiered feeling too at times, can last for days or more, where you just do the absolute minimum required to get through the day.
Sometimes all it takes is a new experience, new interest, new "toy" or some unusual event to wake you up and get you excited and alive again.
Alot of it is mental and if you can get yourself into a powerful and energetic state, with strong goals to go get, you may feel much more natural energy and drive.