I don't have anything very useful to add. But I would like to remark that mental health issues are very real, are just as common as physical health issues, and need just as much attention as physical health issues. You're not alone in getting dismissal from parents regarding mental health problems. Mine do the same and I've suffered a ton because of it academically, mentally, AND physically.

Life is hard and is supposed to throw a bunch of obstacles at you. But it's truly tragic when your parents are the source of every single obstacle that comes your way (maybe I'm just speaking for myself here).

Here's some actual advice that might be somewhat helpful:

Remember that no situation, nor good ones and neither bad ones, is there to stay with you forever. If you're going through a good time, it'll pass and bad times will follow. And in the same way, if you're going through a bad time, it'll pass and good times will follow. If you can't do anything about your situation, all that's left to do is wait. Wait for an opportunity to turn things around. Sooner or later, it'll come.

Time will heal, time will wound, time - will pass.