Funny thing is exercise helps with that (barring disability in which case talk to a doctor), but in general the less you move the worse you feel and it takes a bit to kick in

“Well actually, not so much ‘forgot’ as uhh… How do I say this… I never intended to make the energy. Just didn’t feel like it. Sorry, not sorry.”

The secret is to take in enough mild stimulant (coffee, pre-workout or whatever) that it becomes so unpleasant to do nothing that you’ll do whatever to make it stop.