English words

I have a problem with using English words. I can understand the words’ meaning in the reading material, but when I want to use that meaning, I completely foget many words. Even though I study the words, I don’t know how to use these words correctly. I think many students are like me, don’t you? I want to remember words that I know in my head. I even couldn’t use many words that I have already known, in the writings. I got depressed. I learend the term “fossilization” in second language acquisition class. It means your language level isn’t move for a long time. I afraid about this term. If I had, what can I do for break this problem?