Is it bad that I went to the gym with a chick who isn't my girlfriend?
Why did you go to the gym with a girl who isn't your girlfriend?
That's one of the reasons why I like her
Its okay to want to spend time with someone who isn't your girlfriend. Just be sure that she is aware that you're spending time with her as a friend. You don't want to unintentionally lead someone on.
If that's how you feel about it, I think I should use the gym with my friend again. I really want to hit that.
You shouldn't think of that friend as anything more than a friend. You can't be saying things like you want to hit that.