I have been diagnosed with severe anxiety for almost 10 years. I have been to see therapists, counseling and cbt a number of times for help. So have quite a lot of experience with anxiety unfortunately.
It can be difficult eating out as a Ceoliac but if you suffer from anxiety eating out becomes a lot more difficult. To give an example from therapy regarding eating out, it's perfectly normal for someone with CD to go out to eat and be a bit nervous or worried about being glutened or cc. Especially if it's a new restaurant. In a way being a little anxious can be a good thing as you are more likely to make sure you double check everything will be gf etc. However if you are really worried about eating out and really try to avoid it or prefer to avoid eating out in a new restaurant, then this is not good and the anxiety is a big problem. Like a little bit of anxious when eating out is normal but strong anxiety where you are more on edge and can't relax, constantly worrying will it really be 100 % gf etc is very bad anxiety.
I hope that makes sense? It's kinda hard to explain it in words. But basically a little anxious when eating out is normal but that anxiety in your example about going abroad is not good anxiety. When the anxiety stops you from doing something it's a difficult problem. I'm very anxious about many things non CD related but I also have a number of CD anxiety's including the examples you mentioned eating out or trying a new restaurant even eating a gf product from the supermarket can be difficult for me. I can also relate to the not wanting to go abroad example you mentioned, would make me very anxious, does the country really understand GF, will it be possible to find gf products in the local supermarkets etc etc. Lots to worry about. But this is bad anxiety as it is stopping you from doing something in life that should be fun and enjoyable. That's really what anxiety can do to you, it can stop you from doing the things you want to in life, or make the things you do less enjoyable and instead just a source of constant worry which of course is no good
Have you ever considered going on a cruise ship to Europe? I mention this as we went on a cruise over 10 years ago and it was so easy to eat GF. This was before my anxiety had become really bad so it was easier I guess compared to if I went on another cruise now, but the cruise ships have so many dining options it's probably a lot easier then just going to local restaurants abroad near where you are staying. You could just eat meat/fish, potatoes , vegetables , fruit etc on the cruise, while it may be a little boring it could take away some anxiety of eating?
You mentioned your are anxious about other things too, and most probably have already thought about this, but it might be worth thinking about going for some counseling or cbt to try and help your anxiety? If you find you are struggling with anxiety the best piece of advice I can give you is to speak to someone like your gp about it.
I know this is a rather long post and probably a bit confusing at times but if you have any questions on anxiety I may be able to give some advice or answers.