I'm sorry, but this is such an extreme example. You should not overdo anything, be it meditation, gaming, playing, reading, any sport, even drugs. Drugs also give you a state of mind that, when taken to the extreme, can harm your social life and well-being. That is not a problem specifically of meditation.
You can safely do anything up to the point that it benefits you. The moment your well-being suffers, or you neglect important parts of life, like friendship, you should stop.
> it was just that no matter how much I tried I couldn't predict a future where I weren't constantly in agony
That's a great way to put it. I had a few depressive episodes in my life, I know that these thoughts and feelings are symptoms. The inability to feel, even the hopelessness are symptoms of the disease. Usually, I can even pinpoint the cause of the episode. But another symptom is the inability to imagine a state of mind without depression. And no matter how rational you are, it is very difficult to believe in something that you cannot imagine.