Shop, cart, and checkout pages disappeared

I am relatively new to WordPress, and I set up a site with a premium theme and woocommerce. All was working well, but one day the cart page disappeared. It still showed on the menu, but when clicked on, I got a “404 error.” I found the page in the trash and restored it. I had no idea how it had gotten in there. A few weeks later, the checkout page disappeared. Again, got a 404 error. Found the page in the trash and restored it.

I check the site a couple of times a day to make sure pages don’t disappear, but then today the “shop” page *completely* disappeared–it was not in the trash, the menu (navigation) item was gone. I stayed calm and created a new page called “shop,” and as soon as I did that and published it, the shop was back.

I have no idea how this can happen. I was making no changes to the site at all. I need to know how/why this happens and how to prevent it in the future.

Any ideas?