Exhausted.

When I first got prescribed meds, it was life changing. This was about 5 or so years ago - I was energetic on top of focused, the scatterbrainedness simply took a back seat and I was able to just do things. I miss those days so much because now, even on a high dose of Vyvanse and caffeine, by hour 3 I could take a nap. The side effects remain but I’m left tired, exhausted. I don’t feel like this should be happening, and short of a dose change just 10mg higher, I don’t know what’s going on. My scores were high on the Connor’s test so I truly am attention deficit. Does this just.. happen to some people, or am I missing something? How do you deal with this?