Hi~
 

This is Teacher Rach~ Here are your corrections:

I always believe you will be good.

==> I always believe you will be good or well.

But I am worried about something that you don't eat breakfast.
==> But I am worried that you don't eat breakfast. 

If you love me, you have to take my concern off my mind. ^^
 

You did great~! You didn't have many errors! Just take note of this:

*vocabulary: "well" is usually used to describe someone's condition. "Good" is usually used to describe someone's behavior.

*It will be better to just specify that "something" by connecting it to "worried". Add "that" right after "worried" if you want to add a whole clause.

ex: I'm worried that you don't sleep well. or I'm worried that you're not sleeping well.

I hope the suggestions will help! Keep posting~~