You have an error with your database connection that is preventing the checkout page from fully displaying. None of the styles are being added because of that error.
The cleared cart is probably because you are browsing from: pipingtech.store and your paypal code is returning you to: www.pipingtech.store
You can add a .htaccess rule to force the site to either always or never add www. to the front of your URL so it will be consistent. I can also help you update your code to prevent it from changing when going to paypal.