I don't know if this is the right place to post this, but it seems fitting. Sorry in advance if it's not.

I've lived in the same house for the last 26 years. I've never really liked "sleeping out" or spending time away from home really.

Last month, I got a job in a really cool company, doing something I like. It was sort of my dream job before graduating and it's the first place I sent my resume to, first place I got an interview at and it's now my first job (I got really lucky, if you ask me. I'm still not sure I'll be able to manage the job, I don't know what they're expecting)

The issue is that it's on the other side of the country. Since I got the interview, my anxiety and chronic depression have acted up, making it difficult to see this as a good opportunity.

I've been somewhat faking being super okay and excited about this with my family, because I know they're worrying about me moving to a new city, without anybody from the family around.

Well, I'm now at a friend's house in the city I'll be living in (I couldn't find an apartment in time, adding a lot to the stress).
It's 2AM, I'm leaving for work in 6 hours and starting my first day in 7.5 hours. I've slept about an hour, then woke up crying.

After sitting in bed for an hour, crying and trying to find articles to see if this is normal, I gave up on sleeping and got back on the computer.

So, here I am, kind of a mess. I don't know what to do, I've been thinking about just not going in and not taking the job, going back home.
I know I can't. It's a great job, I need to take this and I won't have another opportunity like this. But my head is, as usual, playing the "let's make you feel even more like shit" than usual, and this time the techniques I usually use to cope and get myself back together (learned in therapy a few years ago) don't really work.

I know it's normal to be sad about moving away, but this feels like a bit much. It's only the first night, so perhaps this is expected, but I worry it'll go on and on for days or week and I'll never get used to it.

Is there any tips or techniques on how to cope with what I'm going through ? It feels like it should be a somewhat mundane thing and not something I should agonize over, but it is.

For now, I'm living on borrowed money until my first paycheck, so I can't really go find a therapist to help. I do plan to, however, once I find a place and get some money.
But in the meantime, I don't know what to do to not feel like a lonely piece of crap 300km from where he should be...