I felt like I needed to use my time more productively.
I felt like I should make better use of my time.
ーI felt like I needed to use my time more productively.
「もっと有効に時間を使う必要があると感じた」
to use one's time more productively で「時間をもっと有効に使う」
ーI felt like I should make better use of my time.
「時間をもっとうまく使うべきだと感じた」
to make better use of one's time で「時間をもっとうまく使う」
ご参考まで!