You've had several posts since July 1, and none have been deleted. And no, your posts are not previewed by a mod or software before they are posted.
You've probably figured it out already. If you use the "back" button instead of the "jump" button after you post, you may need to refresh the screen in your browser to let your computer see the latest version of the website.
I like to use the "back" button to maintain my place in the forum index. But if I reply to a post then use the back button to get back to where I was in the index, that thread is no longer where it was in the index - it's moved to the top of the index.