Hi Ana,welcome to Europe! London is a beautiful city (my favorite in the world), I would love to live there one day. I'm very jealous you get to live there ................
You could maybe try and find other people in your position, new in a strange place who may be going through a lot of what you are going through, or find fellow Brazilians who are living in London.
I hope things get better for you once you get more accustomed to your new city!
