depression isn't a mental illness

So I have depression and anxiety, I have been going to a therapist for almost a year, obviously I have my down days and my ups, but over the last month I've had a lot of downs because I'm constantly busy I either have university or I have work and there is no way of cutting down either unless I quit my job. Which I need. Today I opened up to my partner of three years about my anxiety worries and depression that I've felt over the last few days, I know he tried to be helpful but I only feel anger that he doesn't get it and guilt and upset that I can't be normal. Although some of the things he said like I should "try harder" "I don't see depression as a mental issue" and "that's life" it makes me feel as though my feelings and thoughts are invalid and stupid.