I don’t know why I can’t use my user name to sign in my account and now that I use the same email address to login I can’t find all my tax history and also my information

[VolvoGirl]

How to view all your accounts
https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/many-intuit-accounts-...

It's common to end up with multiple accounts. First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/

If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online.

You can also request a transcript from the IRS
https://www.irs.gov/individuals/get-transcript