YOU SAID:

i stayed up until 3 last night writing a stupid paper

INTO JAPANESE

私は昨夜3時まで愚かな紙を書いていました

BACK INTO ENGLISH

I was writing stupid paper until 3 o'clock last night

INTO JAPANESE

私は昨夜3時まで愚かな紙を書いていました

BACK INTO ENGLISH

I was writing stupid paper until 3 o'clock last night