I’m sorry that you are having issues with balancing your income and expenses. There are a few things that I suggest you take a look at:
1. Are all deposits and withdrawals that appear on your bank statement related to your business?
2. As you entered the info from your bank statement for each month, did you reconcile it in QuickBooks to ensure that what you have in QB matches with your bank? If not, you should watch this video tutorial for step by step instructions on how to do this: https://fitsmallbusiness.com/bank-reconciliation-quickbooks-online/.
Believe it or not the error could be the result of simple typo like accidentally adding an extra zero.
I would also suggest that you compare the numbers on your profit and loss statement to your Excel spreadsheet. You might be able to find the error that way. Worse case scenario, if you know for sure that the numbers in Excel are correct, I would go with that.
If you want to get some help, I would also recommend that you find a QuickBooks ProAdvisor that could assist. Here is an article that I wrote to help you find the right person: https://fitsmallbusiness.com/how-to-find-a-quickbooks-proadvisor/
I hope this info is helpful. Feel free to reach out if you have any additional questions.
All the Best-