One of the best investments I ever made in myself was the booking of my first yoga retreat. I went to Ibiza Yoga in Benirras for one week and this was the first solo trip I'd ever taken outside of work. I was looking at the regularity of flights back to London before I even got there because I was convinced that a) I wouldn't be able to do it and b) that it would be full of weirdos doing group hugs. I was on wrong on both counts.
I had always been scared to go to yoga because I imagined everyone would be so much better than me and that I'd just embarass myself. Doing a retreat is a really great way to just dive in and get over that and get into a practice for when you get back and feel good enough to go to classes. Nobody cares what you're doing, because they're too busy on the mat working though their postures, trying to silence their internal voices (I'm ALWAYS fighting thoughts about what I'm going to eat later on during yoga).
I made friends and gained confidence in myself through travelling and learning a practice which is now one of the fundamental cornerstones of my self-care.