Looking at your responses it seems that you have a good grasp on the english language. Which is good! It means you have all the tools available to you when making conversation. You probably just need more practice. Conversations in non-native languages can be difficult, because you have to come up with an answer on the spot. It's not impossible, though. You'll probably stumble for words and make mistakes at first, but that's perfectly normal and okay.
tl;dr: talk more. Good luck!