Some doctors are asses; only a few really care! You ARE NOT WRONG for feeling unheard and dismissed! It is amazing that you have lost so much weight! You should be celebrated for that incredible accomplishment!
(not important, BUT it makes it relative...to explain my opinion)
I've been dealing with severe abdominal pain AND lower back pain (sitting/laying) for YEARS; no doctor could diagnose thus help me. I kept on...
Years later, during a CT scan for my stomach; they noted my lower spine has crushed vertebrae; hence the lower back pain that a doctor didn't notice from their prior x ray nor the xray reader see it. My stomach issues took years and a dedicated gastrointestinal to diagnose, thus cure. I have been abdominal-pain free to almost one year now!
Prove that A-HOLE wrong! I'm sorry for you, but let that be the STRENGTH to motivate you!
I got great pleasure telling the "previous doctors" what the professional doctors found!