ENTP (F) here. First, let me say, YOU CAN DO IT.
Next about the friend let me say lol. I mean sounds like that guy is just jealous so don't take his words to heart. If he was acting as her friend, he would tell her that directly. I say this as a friend who often is blunt about my opinion of friend's relationships. I'm clearly not a dude, but to my guy friends when I think they're in toxic relationships, I tell them to their face. If I liked someone, and I didn't like their girlfriend, I wouldn't have the balls to tell them because I'd be afraid I'd look desperate, or that they would push me away because they would obviously choose the person they were dating over me.
That aside, anxiety of the unknown and uncertain is uncomfortable, unbearable, but common. It happens to all of us when we move to new places, or start new journeys. For me, when I am in such a period of time, I try to remember that it'll all pass, and all the struggle will become a memory. It's a difficult time in the world, jobs are hard to come by, and there's a lot of uncertainty. There's unfortunately not much I can say to change that. As long as you are trying, other people will be able to see your effort and won't fault you for it. If you aren't trying though, hopefully there are people close to you who will call you out and set you back on track.
In terms of your girlfriend, you shouldn't hold back on those kinds of conversations. They're important and they're exactly the type of thing you should be able to talk about with her. If she's just telling you "not to feel that way", maybe you need to be more direct or open with what you need. For example, maybe ask if you two could have a working day together, where you both work on your own side projects, and she could look over your writing or resumes. It might give her something that she can actually do to be helpful. Give her the chance to help you, its a new relationship so maybe right now she doesn't know how to yet.
Also, if you miss your friends and family and dog be proactive. Call them often, set up video chats with your pet and fam, convince your friends to do movie night or gaming night on discord. I say this as someone who moved to a different country for several years alone. I was really lazy about being the one to reach out before I left, but I learned I had to be the one to reach out because I was the one who had left.
TLDR; Dunno if this helps, but good luck. Reach out to people, and the people who matter won't hesitate to help you through this. It's not that you're not trying hard enough, that's just doubt creeping in. You suddenly have to do everything new all at once and mostly alone, it would be a hard time for anyone not just you, so keep on keeping on.