Lou, here is a step-by-step guide if you really want to get somewhere in life.
1. Check your ego. Actually have a think about your life, and think about what kind of legacy you want to leave. Have some fucking humility and think about something other than yourself for once.
2. Stop using Twitter if you can't moderate yourself at least some of the time, and stop browsing your own thread, while you're at it. Who cares what some autists on some internet circlejerk say about you. The less you think about that shit, the less power it has over you. It sounds impossible, but it's true. But then, that kind of thought pattern would make you basically immune to being a lolcow anyway.
3. Get your health sorted out, physical and mental. This is important, especially the latter, for reasons discussed above. Of course you're miserable, because deep down you know that something is fundamentally wrong, when you're starting down middle age and you don't have anything to show for it. My partner is a psychiatrist, which means you have to go to med school to be a doctor first, and *then* learn your specialty. This takes about a decade, and he has done all this, with his own mental health limitations, and he is younger than you. Really have a think about that. If that does not light a fire under your arse, nothing will. The first steps you need to take are to get your physical and mental health squared away. Trust me, you do not want to find out how this ends if you keep going the way you are.
4. Use the internet to do an online course or something, get a hobby, get a social life, get out of the house more. There are hobbies for literally just about anything. There are bound to be furry meets nearby, if you must stay under the envelope of the fandom at all times. Otherwise if you have an interest in something, there's gonna be meets for that. I have interests in electronics, cars, a little bit of metalworking, stuff like that. There are meets for all of these things, sometimes under the same roof. Seriously, if any of you kiwis have an interest in anything vaguely technical, see if there is a Hackerspace or something you can go to. It really is an engaging thing to go to, and I have a small handful of project ideas swirling around and maturing in my head.
That's really it. When you're depressed, you hardly feel like being a social butterfly; I get it. That's why you need to start taking your own physical and mental health seriously. Go to your doctor's appointments, and check your ego at the door. You don't know more than your doctor. Even your run of the mill general practitioner has spent at *least* half a decade of their life purely studying. Your psychologist, psychiatrist, etc, has spend at least a full decade learning this. Your ego will not get you anywhere. Your doctor is going to tell you to do things which are uncomfortable. Listen to them, and understand that they have your best interests in mind. Twitter is not a tool for medical advice. Don't use it as one.
Am I done? I think I'm done. Maybe.
TL;DR Spend less time on Twitter, more on yourself.