YOU SAID:

I eat my cat on thursdays only

INTO JAPANESE

だけは毎週木曜日に私の猫を食べる

BACK INTO ENGLISH

Only the weekly Thursday to eat my cat

INTO JAPANESE

私の猫を食べるのは毎週木曜日だけです

BACK INTO ENGLISH

I eat my cat only every Thursday

INTO JAPANESE

私は毎週木曜日だけ私の猫を食べる

BACK INTO ENGLISH

I eat my cat only every Thursday