All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is unlawful for the Muslim to eat any meat that is not from an animal that is slaughtered according to the Sharee’ah.
Allah Says (what means): {And do not eat of that upon which the name of Allah has not been mentioned, for indeed, it is grave disobedience.} [Quran 6: 121]
So, Allah has prohibited Maytah (animals killed or that died naturally without being slaughtered) because of its harmful effects in this life and the Hereafter. Allah Says (what means): {They ask you, [O Muhammad], what has been made lawful for them. Say, "Lawful for you are [all] good foods and [game caught by] what you have trained of hunting animals which you train as Allah has taught you.} [Quran 5: 4]
So, repent to Allah, seek forgiveness as much as possible, and supplicate Allah to help you repent in the best way and ask Him to protect you from the bad omen of eating what is unlawful.
For more benefit on meat of animals slaughtered by the People of the Book, please refer to Fataawa 82323, 82065, 81234, 393961, 330952, 82899, and 84072.
Allah knows best.