YOU SAID:

i have become very very depressed over the last year and a half

INTO JAPANESE

私はこの1年半で非常に落ち込んでいます

BACK INTO ENGLISH

I have been very depressed in the last year and a half

INTO JAPANESE

私はこの1年半で非常に落ち込んでいます

BACK INTO ENGLISH

I have been very depressed in the last year and a half