I think you should find another doctor for a second opinion, and/or a specialist in ADHD. That’s also okay to do. 🙂
Everything I’ve read on the subject indicates that it is well established that different people have different levels of success on different types of stimulants, including extended release vs. instant release as well as amphetamine based vs. methylphenidate based stimulants. Your doctor should be taking your reports of success/failure seriously, she/he is not doing her/his job otherwise. Your know your experience better than any doctors. Doctors only know the safe parameters within which to help you find what works for you.