Page taking too long to open

[ Moderator note: moved to How-to and Troubleshooting. ]

I need help on how to make a page that I want to open to open faster. On my site I have an page: “Post New: This page is just not opening for me. I see that it tries to open but then it does not open.

I also tried to restore many pages that my last programmer spitefully put all my pages in the trash. As I tried to restore my pages back to my site I think that I most have clicked the wrong button because on the top of the page there is a lot of content lines that appear above the page that I want to open!. my other question is how do I make that top section disappear or delete it?

Below is a sample of the content that appears on top of page:
Compilation failed: nothing to repeat at offset 1 in /home/letssalsanow/public_html/wp-includes/class-wp.php on line 231

Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/letssalsanow/public_html/wp-includes/class-wp.php on line 232

Any help in this matter will be greatly appreciated!.
Henry Barrow
Website: letssalsanow.com