It sounds like you have depression messing with your mind. I empathize a lot, since I’ve been in that place.

The thing I will say is that most of the problems looming over you are paper tigers. They have far less substance than your mind is telling you they have.

Unfortunately, the lesson I learnt was that no-one will actually help you. People will make a lot of nice noises, and will even accommodate you, but they won’t help. That needs to come from you. Don’t get me wrong, it’s terrifying, but it’s like neo taking the red pill. It’s not that he’s not scared, but that he knows the other option is not where he wants to be.

Up until now, I’ve just been making nice noises, so onwards to some practical advice.

Appearance.

You mentioned you are a bit of a lock in. Often you can get your appearance slip, don’t let it. It can be as simple as keeping personal hygiene sorted, and wearing “smart” clothes when you go out. They don’t need to be expensive, just look nice. For men, a button up shirt and some chinos can make a huge difference to how others react to you.

Socialising

As painful as it is, social skills are a necessary tool of life. They also go rusty VERY quickly. This leads to a feedback loop that leaves socialising as a terrifying idea. Your goal should be to have a short conversation with a “stranger” every day. This could be as simple as asking a cashier how their day is going, or asking for directions from someone out and about.

At this point you’re probably mentally whimpering “I can’t do THAT!”. You actually can, and most people will actually respond positively. The part of your mind saying you can’t is the problematic part. Recognise that it is trying to help, but that its advice is bullshit.

Anchoring

The above is the most basic stuff you should be aiming for. The most important thing however is to establish mental anchors. Think of them like the bolts climbers use for their ropes. Reaching them is hard, but once they are embedded, recovering from a fall gets a lot easier. You also preferably want several anchors. Sometimes they fail, it happens. If you only have one, that can cause problems, but if you have several, repairing the lost one becomes a minor annoyance.

A good anchor is a commitment you can lean on and say “that’s a positive thing for me” even when you really don’t feel it. Groups, or periodic events work best. Meet-up is a good resource for finding things and ideas. Some more ideas below.

Gym - a regular fitness regime does wonders for your mind. It also gives organic opportunities to talk to people.

Sports - often cheaper than the gym, find a regular sport meetup and go along. Don’t worry about being completely rubbish at the start. Most people respect effort, and you will see the payoffs quite quickly.

Martial arts - similar to the above, but a bit more formalised.

Dungeons and dragons - one of the classic “weirdos unite!” socialising methods. If you’re polite, and followed the hygiene advice earlier, you’ll find most groups extremely accepting.

Makerspaces - if you’re engineering/creative then these make excellent opportunities to socialise. I actually ended up establishing one. It turned out I wasn’t the only weirdo in the area who wanted somewhere to socialise on our terms.

The pub - a classic, but often doesn’t fit a lot of people’s mindset.

Cinema groups - cinema has gotten a bit expensive now, but once you have a job again they can be a good social event. You get to hang out with a group for a while, without needing to talk much. Once the film is over, you have an automatic topic of conversation.

I’ll leave things there. Just remember, that voice in your head means well, but is lying to you. The looming monsters are paper thin, but only you can punch through them.