YOU SAID:

I found that my dog had been lost since yesterday

INTO JAPANESE

私の犬は昨日から迷子になっていたことがわかりました

BACK INTO ENGLISH

I found out that my dog had been lost since yesterday

INTO JAPANESE

昨日から犬が迷子になっていることがわかりました

BACK INTO ENGLISH

I found out that the dog has been lost since yesterday

INTO JAPANESE

昨日から犬が迷子になっていることがわかりました

BACK INTO ENGLISH

I found out that the dog has been lost since yesterday