When I was in my late teens, doctors wouldn't take some of my complaints seriously or even bother to investigate. Also, when I would miss school for being sick, the school Social Worker literally called me a hypochondriac to my face. My mother got involved and called her out on it, because she knew something was going on with me aside from my mental health problems. I had certain doctors who labeled everything automatically as caused by anxiety, when I knew there was more to it.
Also, the school nurse said I had something 'seriously wrong' with my mind-body connections, so it wasn't until later when I got a different primary care doctor who actually did find I had some underlying legitimate health concerns.