Helllllllllllp

This sentence "I was writing a book." is correct in American Enlish, right?

I don't know why I always say that I'm wrong. I always want someone to check my sentences in English even if I'm 100% sure about it. I really get confused because of this. It makes me forget the correct form of answer because I think about it a lot. I really need some advices to get over this problem. I really like English and I don't want to loose what I've learned. Some times I ask questions and I know the correct answer and if the sentence is correct or not, but I just don't feel satisfied and good until I ask someone who is really good in English. Like know I know that we add "ing" to the verb that comes after was and were but I don't know if myself or my brain is saying that there is something wrong with that. Please help me.

I really appreciated your answers.

Thanks