While it is true that grammar is important, the main thing is that you are communicating your message. It is nearly impossible to master perfect grammar. Whats's more, which grammar is it ? There is such a thing as spoken grammar as opposed to written grammar. Please don't be intimidated by perfect grammar usage . Communicate with us the best you can. We are really more interested in YOU as a person, not your mastery of grammar. Without that pressure, you can freely communicate with us and then gradually build your grammar excellence.
I think you are afraid that people are judging you every time you speak but that is not true. I would much rather talk with someone who maybe isn't perfect in English but has a nice personality than some cold, humorless or arrogant person who speaks perfect English.