Yes, if you can itemize on your 2019 tax return, then you may be able to claim gambling losses. You can read more about it here and here. 

Thank you! So I can still add in my gambling winnings and losses AFTER they sent me the letter of what I owe? Because if I add in what I lost, I will be paying a lot less then the irs “proposal letter” 

Yes, you can add you gambling losses even if the IRS sent you a proposed changes letter. See Can I deduct my gambling losses?

You may need to amend your 2019 income tax return and send it in with the IRS letter.