Did you use Turbo Tax? Turbo Tax automatically gives you the higher amount. How much is on your 2018 line 8? What do you think the amount should be?
You are not confusing the personal Standard Deduction/Itemized Deductions with your Business Self Employment expenses?
Yes you can amend. https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-...
