Apparently Vyvanse isn’t supposed to be a permanent medication?

I’ve been taking Vyvanse for a few years now and decided to re-read the leaflet that comes with the medication out of curiosity. I’m a bit confused about something I read though:

Apparently, Vyvanse isn’t supposed to be taken forever and that if you’ve been taking Vyvanse for over a year, your doctor should stop the treatment for a short time to see if you still need it. This implies that Vyvanse is supposed to have some kind of permanent effect on adhd symptoms? Also, I haven’t been contacted at all by my doctor about this.

The thing is, during periods where I haven’t taken it, either due to running out or just needing a break, my adhd symptoms come back in full swing. Probably even worse than they were before actually. I’ve noticed no improvement whatsoever. But when im on the medication, I feel great. It also helps with my IBS symptoms for some reason. So when im not on it, those symptoms come back as well.

I was planning on taking this medication for my whole life. Is that not gonna happen? 😭