Op, it sucks I know. Some people just don't understand mental health. If you were physically unwell, the likelyhood is that you would get more support. Mental health however, if you haven't experienced it, you just don't really comprehend it.
I had a breakdown three years ago and I'll never forget my father giving me a lift to an emergency gp appointment (I was so unwell at this point I was genuinely convinced I was dead and in hell, psychotic thoughts) and telling me he could only do it the once as he was busy.
My mother however, who understands mental health, was there every step of the way, so much so she came close to losing her job trying to help me back on my feet.
You do learn who is there and who isn't when things like this happen. However I try my best not to judge because I do firmly believe people don't get mental health problems.
I will also say that when someone is very depressed, they become very self centred. This isn't out of meanness, it's part of the nature of the illness and it can be very wearing on those trying to support. Sometimes it can even lead the supporting person into depression themselves. When I was really unwell, all I could think about was how much I was suffering, I was unable to consider how those around me were struggling with my illness whilst trying to go about their own lives too.
Unfortunately I also understand how difficult it can be to get appointments and the lack of mental health services available. I would try asking for a gp to call you for a telephone appointment, they usually do the same day and they can then arrange an appointment for you. Keep trying and don't give up.
It hurts a lot when someone as close as a parent doesn't seem to care when you are suffering. As I say, I won't ever forget my father saying that to me. It affects your self esteem. But at some stage, when you are in recovery, you learn that when people let you down, you don't have to emotionally invest in those feelings.
I hope you get help very soon x