The same thing happened to me, but my doctor started me on XR. For some reason, I never get the “second wave” of the XR, so it ran out after 4 or 5 hours and left me with worse symptoms than taking nothing, and a very aggravated mood to boot. Even with a booster IR for the afternoon, it still didn’t seem to work. Now I’m on IR only, and it works like a charm.
Yes, it’s a pain to have to take several doses throughout the day, but it gives me the the concentration and focus to deal with it. 🙂
And ditto what Penny said.