How languages change everything

Today I am going to write in english.
For two reasons: first because I am living in London, and now I have more friends who don't understand portuguese than ever, second because the subject of this text is actually this: how languages change the way people see you.
As a portuguese person, I am fluent in portuguese. I am used to have all sort of words in my lexico to say and demonstrate whatever I want to tell. And things go fluently whithout thinking to much or having to chase words to explain what I want to explain. Basicly I am able to be more the real me.
Because no matter how fluent I am in my English, I always feel there are millions of unknow words still to know. And no matter the millions words I know already, I will always be speaking a language that is not mine.
Now a days I feel I am not talking with my heart but with my brain. I am feeling like a "Mercedes" that became a "Fiat Uno", from running and working fast to a slow processing. Spontaneity become hard.
The way you say something funny in Portuguese, will never be so funny in English, because in your mother language it has a different result than if you just say it in other language. In English, you also have many different ways to say something in a funny way, but you just don't know how. And if you know how and everybody laughs, it doesn't sound so funny to yourself anyway, because is not your language, it's not as you firstly thought it, and because you probably spent twice of the energy to tell that funny something than the energy you would spend if you were speaking your natural idiom. It is a mistake to think that literal translations work, because the majority of times.. they don't. Start getting used to "yellow smiles".
So, the problem is not the English itslef. I lived almost two years in Barcelona and I learned Spanish also. But even Spanish being so much more similar to Portuguese than English is, I remember feeling out of my heart the same way.
I had became someone I am not, or maybe I am the same person, just not so easy to know, but definitly reactions are different.