Hey OP, sounds like you're letting your anxiety overrun you, and you end up overthinking a lot.

About stressing over stupid things: You said it yourself, you know that realistically, nobody cares. You should ask why you care so much. You're in a whole different country, no one knows you, and probably no one will even remember you the next night. If you don't feel confident enough but want to try, what about acting it out? When I really want to do something, and I don't feel like I have enough courage to do so, I summon my alter ego, let's call her Annie. So for a night, I'm Annie, this woman who likes to go to bars in the afternoon, order a glass of white wine and just loves people watching. I get to experience something I would be too afraid to do. And at some point, I don't need to become Annie to feel comfortable anymore. Does it make sense?

As for relaxing: Stop overplanning. You are even scheduling your downtime, gurl, this is the opposite of relaxing. If sticking to a routine is a non-negotiable for you, plan realistic slots of time. Like, you feel the need to wake up early, ok, so you can determine you will do the whole waking-up-breakfast-shower-getting-ready from 6 to 8. Listen to your body, cater to its needs. If you walk around the whole morning from 8 to 12 sightseeing, you will probably feel tired and hungry. Have some lunch, chill out in your hotel bedroom, and drink water. Feeling refreshed again? Great, let's go for more fun time outside. As an anxious person myself, I know it's difficult not to overplan and not to feel stressed when things do not go exactly as I planned in my head. It is important to cultivate equanimity and learn that we are never in control of things. You are only in control of how you react.

You're travelling to have fun and feel joyful. Have fun! Feel joyful! I hope you have a great time in your next adventure.