If you have grammatical issues in your writing, we need to solve that first. Borrow a book from the library and read it for 10 minutes every day, or read something intellectual from The Economist (you can read this online), or read something else that is interesting to you. What you read doesn’t matter. The point is to consistently expose yourself to good grammatical usage. After a couple of weeks of daily reading, grammar will begin to feel less confusing.
If you have a limited vocabulary, do the same exercise. Pick up a book and read it every day. Look up new words on Google. Be proactive with your English. You will probably live to 80 or 90 years of age, or even longer if scientists come up with epic, amazing anti-aging pills in the near future. Perfect your English now, so that you won’t need to worry about your English communication skills for the next 70 years of your life.
Pay close attention to how I use my grammar and vocabulary during the Full Analysis videos, and you can always ask questions on the IB LitLearner Facebook group.