Is ADHD a reason not to do a PhD/PsyD?

Well honestly I just got into my dream PsyD program but I’m feeling like I might not be cut out for it long term. To be honest I can only do maximum 6 hours of school work a day period before I get tired. And I’m not sure if that’s enough to sustain me through grad school because even that focus can be hard. I’ve heard there’s a tonnnnn of reading which I can barely get through for my undergrad and current masters, despite doing really well in all classes (straight A’s in psych).

I also have been feeling overwhelmed with grading the testing part of assessment, the whole testing process seems tedious and long — despite me really loving the intake and writing part of assessments.

Are these valid concerns or am I just being lazy?

Edit: Wow!! Thank you so much for everyone that commented. You guys gave me so much confidence, and also things to think about, as I make this big decision. I appreciate you all :)