Why is English difficult for me?

English has been a second language in my life for about two years and all this time I felt there are some barriers between me and the this language. I think study another language can be very hard to many people. For me one of the worst things is the pronunciation, I have several problems about how is correct spell and speak some words and this makes me very uncomfortable, because somethings I think that I can speak the word correctly, but when I say the reality is different, like for example the words: rough, desert (verb and adjective), dictionary. May seem easy words, but who is not accustomed with them is too complicated. Other problem is the difficult to talk to someone that is fluent in English or is American, this is because I know that person knows more than me and with this I don’t say everything that I want or I can with fear of making mistakes. So, in many situations I just say the easy things, like: This is true or It’s the same thing. I have noticed that I don’t think much before speaking, I just say, what makes me confused and talk things wrong. In my point of view I have another important weakness, which is the grammar. In general English grammar is similar with the Portuguese, but some rules are hard to me. I need to be very careful to don’t make mistakes, but is difficult when I’m nervous or when I need talk to another person with English better than mine. I always make confusion with very simple things: change the DOES for DO or DO for DOES (he DO the homework), I put the verb in the wrong time, for example: I was studied yesterday. I have some doubts about the sequence of sentence, put all together (verb, noun, adjective, adverb) is a little problematic to me. How I’m learning about this things I always think that is not correct even if it is. Learn another language requires time and dedication, no one can learn without trying and challenges will always appear, but I must be prepared, as this is part of learning.