How did you file your business taxes separately? Or didn't you file it at all? A Single Member LLC is a disregarded entity and you file it on Schedule C in your personal 1040 return. UNLESS you set it up as an S corp in which case you do file a separate 1120-S business return for it.
You need to amend your personal return to add schedule C for it. 2023 is now a prior year. How to amend a prior year return
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
