Mate it's hard not to get depressed when speech / communication is letting you down - such a critical aspect of life. I have been in your situation, like it's not even worth communicating any more. I eventually got out of the dark hole I was in with a bit of time and more acceptance of my speech. I still struggle daily, but not as much as that dark time. Sorry i cant help too much. Have you thought about medication? i.e. anti-depressants?