You did the right thing by reporting the winnings even if the casino did not report it.
The IRS very specifically states that "Gambling winnings are fully taxable and you must report the income on your tax return. Gambling income includes but isn't limited to winnings from lotteries, raffles, horse races, and casinos. It includes cash winnings and the fair market value of prizes, such as cars and trips."
If you feel you could offset the winnings by losses, you could do an amendment to include any losses you may have had in 2017 and possibly get some of the money back.
Here is a link on losses.
You did the right thing by reporting the winnings even if the casino did not report it.
The IRS very specifically states that "Gambling winnings are fully taxable and you must report the income on your tax return. Gambling income includes but isn't limited to winnings from lotteries, raffles, horse races, and casinos. It includes cash winnings and the fair market value of prizes, such as cars and trips."
If you feel you could offset the winnings by losses, you could do an amendment to include any losses you may have had in 2017 and possibly get some of the money back.
Here is a link on losses.