Frustration with Diagnoses and Workplace Discrimination

I'm honestly frustrated with my diagnoses, they actually made me lose my first full time job. People accused me of using it as an excuse or lying and that HR didn't get notice even though I sent in an application mentioning that I am disabled. I'm told to simply get over it, to stop taking so many breaks, and to work harder as I supposedly hadn't been able to work at the intensity of others. It's frustrating being invalidated as my illnesses aren't something you can see simply by looking at me and therefore are viewed as less real to society. Also the issue of fatphobia in the workplace was something I wish someone warned me about because I'll take the same breaks as someone else but I'm lazy just because I seem to weigh more, or I'm whiney because I'm trying to advocate for myself when nobody else will so I don't need a hospital trip. I just am so frustrated with the lack of understanding society has for people like me, even though I'm still fairly young that doesn't make my problems inaccurate even if they are more unlikely in younger individuals.