YOU SAID:

I'm gonna complain all day because I got my period at like 12 am

INTO JAPANESE

午前12時くらいに生理が来たので一日中文句を言うつもりです

BACK INTO ENGLISH

I got my period around 12:00 am, so I'm going to complain all day.

INTO JAPANESE

夜中の12時頃に生理が来たので、一日中愚痴を言います。

BACK INTO ENGLISH

My period came around midnight, so I complained all day long.

INTO JAPANESE

生理が夜中くらいに来たので、一日中愚痴を言っていました。

BACK INTO ENGLISH

My period came around midnight, so I complained all day long.