My Problem

I realized that my problem is not that i don't know what to write, but that i don't know HOW to write it. I think of all these ways to support my ideas, but then when it comes to putting pencil to paper, i get a blank. Or when i do get words that make sense onto the paper, then the sentences together don't really have a meaning.
i think that writing is the weirdest thing. Unlike math, where there is only one version of it, writing has so many different versions its hard to keep up. u can write soemthing that little kids can easily read while writing something with the same meaning for elders but those same kids don't understand!!!
it gets really confusing, because when im told to write a certain way....i get even more lost... is there no such thing a 'just writing'??