The difficulties you're experiencing with QB Self-Employed can be challenging, chelsides. Let's get this sorted out together so you can continue doing your business.
To address this as quickly as possible, could you please confirm the name of your bank or if you encountered any specific error messages? This information will greatly assist me in diagnosing the problem more accurately.
In the meantime, please take a moment to review the Filter date settings in your QB Self-Employed account. Ensuring that dates are set correctly to encompass the full range of your required historical data might bring those missing entries back into view.

In addition, you can assign categories to the transactions to ensure they are allocated correctly on the relevant line of your Schedule C: Categorize transactions in QuickBooks Self-Employed.
You can always get back to this thread if you need additional assistance managing and connecting your bank or transactions, chelsides. The Community is ready to help.