He says I can control my mental illness. How do I explain to him that it's beyond my control?

So I was talk to my boyfriend yesterday. I've been diagnosed with Major Depressive Disorder and severe anxiety a long time ago. I'm on a number of medications including sedatives and tranquilizers. I have a history of self injury and when I get sick I have no control over what I say or what I do, I'm impulsive, I'm irritable, there are days I have unexplained crying spells, I can't get out of bed, I won't leave the house, I won't get dressed, shower, talk to anyone. When it's bad it's really bad and yesterday me and my bf got into a discussion about depression and he told me that if I really wanted to, I could control it. That I don't need medication, that the docter's are all wrong, that I'm not sick at all, I just need to learn to have some self-control and if I really wanted, I wouldn't be like that. It hurt me because I can't control it and I wish I could, because it F-ing sucks to feel the way that I do. I wish he'd understand instead of thinking that I'm weak. I feel like he's talking about something he knows nothing about. How can I explain to him that I really am sick? AND why is he being like this? I need opinions and help please. Thanks.