Some might say that you don’t need to study grammar to be a fluent speaker and that all you need is an extended period of exposure to the language - but I personally can’t help but doubt the idea. One may learn a variety of expressions and communicate their ideas in one way or another, but the issue here must be the degree of precision. Even grammatically correct sentences can lead to misunderstandings, so it’s no wonder that grammatically inappropriate sentences can produce a number of them, rather unnecessarily.
Studying grammar is not everyone’s cup of tea and I understand your struggle as a fellow learner. Think of grammar as essential building blocks. Plus, sometimes grammatical rules can give you a new insight and perspective regarding the phrases you already know.