Personally, it was terrible of him to do that (in my opinion). It may be the case that he was very pressured by all of your emotions and couldn't take it anymore, but he could have told you all of this & have a chat about it saying what he thought rather than bitching about you. But, have you ever considered that he DID not say you were a drama queen?
Maybe, it's the case that it got too much for him, and he thought you were too clingy perhaps. But, a good friend sticks about through trouble and he obviously did not: otherwise he would have talked about how he felt too.
Moreover, depression is an illness, so who said it wasn't is wrong, and very insensitive. However, I think that what you are doing to yourself needs to be dealt with more professionally, as it must have been a huge weight on your "friend". I've dealt with a friend who did this & it's bloody hard, so you must understand the emotional consequences of the friend too. What I'm saying is: I think you need to see somebody as you can't keep living like this. Whatever it is that makes you do this must be sorted as it's been going on for too long. I know your "friend" probably meant a lot to you, but it's better that you deal with this with someone else.
Also, I think maybe you should try and talk to your friend, as I see this situation only reinforcing your misery. Despite him being a prick then, you both need to understand what is happening, and falling out will not help your situation.
Sorry if i seem patronising & I hope you work something out. Also, hope your depression gets better, but remember sometimes it is hard for people to understand.
Gemma (sorry for waffling)