Quase nada a se corrigir, tenho certeza que a maioria dos erros foram de falta de atenção, mudei um pouco o texto para soar melhor, sugerindo algumas mudanças em parenteses().
I have some serious doubts as to my reading. I don’t know what type of English I should read to expand my vocabulary. I have come across two varieties of English lately. One of them seems more formal and the other one less formal(less so). The first one we are used to see it(não está errado, mas repetir o sujeito soa extremamente mal) in magazines and newspapers. The second one we find (it) in literature books, the so-called “novels”.
I don't know what to do anymore in this regard (Regarding this, "i dont know what to do anymore"/"i am at a loss"/"i'm at a loss regarding this") . I have been reading both types, formal language and informal language(I've been reading formal language and informal language(both)). I’ve noticed that they are very different from each other "regarding" the vocabulary used in each one of them - if you know what I mean. For example, in a magazine or newspaper, we will hardly see a casual dialog between two characters as we usually see/read/do in novel books. When I’m reading a novel book, for instance, I barely see those very formal linking words, like(such as), "therefore", "furthermore", "nevertheless" and so on, but it's very ordinary to see this words being seen/used in magazines and newspapers.
I'm in divided about whether I should read magazines and newspapers or novel books. At times, I think it’s better to learn the English found in the novel books, because its English seems more (like real life, more) practical for our everyday life. On the other hand, I think the formal English will be better for my writing and also my speaking skills, once it is more understood "all over"/"around" the world. On second thought, it just occurred to me that, maybe, novel books have actually, a semi-formal language and not an informal language in itself. I don’t know, I just can’t decide. It has been a difficult question.