It will feel very rewarding when it goes well. Don't take an impromptu phone interview (big mistake I made), tell them you have to reschedule and ask if you should prepare for any technical/role-related questions. Then just grind the basics and hope for a nice interviewer. As for English, I have the same problem with it. Makes it even more important to prepare the right words in advance so you don't waste mental energy on that. Just keep it short and easy on the important facts. The rest is more forgiving as they don't expect people to have the perfect answers to everything.