I’ve been there too.
Even before reading post #19, I was going to advise you (DigitalC) to look for a better job (and/or work harder at your current one). For a couple reasons. One, having money, more than just the minimum you need to get by, means you have options. And feeling like you have options, and trying some of them out, goes a long way toward getting you out of misery and depression.
The other reason is that the job thing, and the getting in shape thing, and a few other things fall under the heading of Do something that will give you a sense of satisfaction or accomplishment. This could be through a job; it could be through achieving some health and fitness goals, it could be through creating something (e.g. if you’re some sort of artist or writer or craftsman), it could be through helping someone out (e.g. some sort of volunteer work), it could even just be cleaning up or redecorating your room. This, I think, will help your confidence and self-worth, wihch will help you get your mojo back socially, sexually, etc.