Shopping cart won't hold more than one item

I wish I knew what I did. I had created my own product pages - each page displaying its own category of products. They were located in the dropdown menu: Store > Products > then I had the pages of categories displayed. Under the Store page I still had "cart" and "Order Status." I don't know how I did it, but I somehow tried to get the shopping cart to be it's own page and not under the Store page. After that, only one item can be added to the cart and as soon as you add a new item, the older one disappears. I've tried uninstalling and reinstalling from word press and from the web host to see if I could start fresh, but it saves all my settings and the cart is still broken. I reset the original Store > Products, Cart, Order Status drop down menu and tried to get rid of my own short code product pages, but that didn't help either. Thank you in advance.