If anyone with ADHD or experience with vyvanse can help me out it would be greatly appreciated!

I was diagnosed with inattentive ADHD a few months ago and my doctor started me on 20 mg vyvanse and told me that I could build on dosages each day to see what worked best for me. We believed that 60 mg was the best for me. Now, after 3 weeks of being on 60s I am beginning to think there is something wrong with it. I’m not sure if it’s too strong, weak, wearing off, or just the wrong med for me.

A typically day with it would be:
7am: take it with a large breakfast and protein shake
8am: can feel it starting to work
8-11am: motivated, getting work done and staying focused
11:30am: getting tired, headache, irritable, my anxiety heightens, focus is gone, and I start zoning out.
From this point on I feel like I can’t get anything done, I feel like I just want to shut my eyes or nap. I struggle to make it through a paragraph. But I don’t have any symptoms of overfocus, jitters, jaw clenching, increased heart rate, etc. I have heard about the zombie state, is that what I’m experiencing?

So with that being said, I started to think it was just metabolizing too quickly and wearing off. When I started looking into it there were a lot of people who take a dose in the morning and another in the afternoon. So there was one day when I took a second dose (30mg) around 2pm to see if the was the problem and I felt as if I didn’t even take another dose. All of the negative symptoms listed before just stayed the same- I just felt tired and crabby.

I have also focused very closely on my water intake, diet, and exercise to be sure that wasn’t the issue. Everything in regards to those are great so I know that’s not the problem.

Any input on this would be GREATLY appreciated