I just can't face another day

I know there's a lot of depression on this site - so my post will be nothing new.

I'm 45. I used to work in PE on the deal side. I was ok, interesting work. But for the past 10 years I've been in IR only. It's so depressing. Sitting there and pushing out emails helping PE funds raise money as a sort of unlicensed placement agent, all alone in a room, year after year. No brand, no employer, no co-workers. I just can't take it anymore. 

I'm just furious all the time. I hate the churning out of emails and investor outreach. Same thing, hour after hour, day after day, year after year.  I go home bitter and angry and am a bitter resentful husband and father because I can't stop because I am the sole supporter of the family, but I just hate that I'm in this position and have to keep doing this work. So... I quit.  I'm done. If I keep this up I'm going to dine on a bullet so I am just done.